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Abstract

Maize is a key food crop in West Africa, where Benin, Ghana, Burkina Faso and Nigeria account for most of the regional production. Storage pests are major constraints in the maize value chain, with losses reaching 30%. Simple, low-cost triple bagging technology (now known as PICS – Purdue Improved Crop Storage) originally developed for postharvest storage of cowpea was evaluated for applicability to maize storage. Thirteen test units employing PICS bag were set up in July and August 2012 at eleven localities in Benin, Burkina Faso and Ghana. Each trial unit consisted of 3 or 4 PICS bags of 50 kg capacity and 2 woven control bags. We used locally purchased naturally infested maize that had relatively high levels of infestation with Prostephanus truncatus Horn, Sitophilus zeamais Motschulsky, 1855 and/or Rhyzopertha dominica (F.) (seven localities) or lightly infested maize showing little or no evidence of damage (four localities). After 6.5 months of storage in PICS bags, there was 95–100% insect mortality at all sites. The percentage of damaged seeds and the 100 seeds weights in PICS bags were unchanged from what was recorded at the time the experiment was set up. Seed viability was well maintained; germination rates of seeds from the PICS bags did not differ from that observed at the beginning of the experiment. Aflatoxin tests were carried out on 245 samples, with 53% having levels above 20 ppm in both PICS and woven bags. Samples from PICS bags tended to be less contaminated than those from woven bags. PICS bags can be used for maize storage even in areas with high prevalence of P. truncatus, but storage of maize should begin soon after harvest and drying to minimize bag damage that can occur when very high numbers of P. truncatus are present.

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... Maize postharvest losses vary significantly by crop, stage in the value chain, and geography but may reach up to 20% or higher [1][2][3][4][5][6]. Losses are primarily caused by feeding associated with population growth of pests (particularly insects, rodents, etc.) and the presence of mycotoxins [7][8][9][10]. To deal with postharvest losses during storage, farmers employ Conventional polypropylene (PP) woven bags were used as controls. ...
... However, after seven months of storage, all insects had died in hermetic bags while there were still live insects in the PP woven and the ZeroFly ® bags. Hermetic bags are known to be effective at suppressing insect development and reproduction in stored cereal and legume crops [7,8,18,24,36,37]. Our results corroborate findings of previous studies comparing several hermetic technologies in the Sahel and other regions in sub-Saharan Africa: SuperGrainbag™ and PICS™ bags in Niger for preserving cowpea [30]; PICS™, SuperGrainbag™, and AgroZ ® bags in Tanzania for storing maize [22]; PICS™ and SuperGrainbag™ for storing maize in Kenya [38]; PICS™ and SuperGrainbag™ for storing maize in Malawi [28]; and PICS™, SuperGrainbag™ and EVAL™ (Kuraray) bags in Zimbabwe for maize storage [29,31]. ...
... In the control PP woven bag, there was an increase of 32.0% of grains with holes and 10.3% weight loss after seven months of storage. This weight loss, though substantial, was lower than the 20-50% reported in other studies after 6-6.5 months of storage of maize in Benin [7,46,47]. The grain damage and the weight loss in PP bags were due to the high level of insect infestation. ...
Article
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Several postharvest technologies are currently being commercialized to help smallholder farmers in sub-Saharan Africa reduce grain storage losses. We carried out a study in Northern Benin to compare the effectiveness of five technologies being sold to protect stored grain. Maize that had been naturally infested by insects was stored in four hermetic storage technologies (SuperGrainbag™, AgroZ® bag, EVAL™, and Purdue Improved Crop Storage-PICS™ bags), an insecticide impregnated bag (ZeroFly®), and a regular polypropylene (PP) woven bag as control. Oxygen levels in hermetic bags fluctuated between 0.5 ± 0.0 (v/v) and 1.0 ± 0.3 (v/v) percent during the seven months of storage. No weight loss or insect damage was observed in grain stored in any of the hermetic storage bags after seven months. However, grain stored in ZeroFly® and PP woven bags had weight losses of 6.3% and 10.3%, respectively. These results will help farmers and development agencies when making decisions to use and/or promote storage technologies to reduce postharvest grain losses.
... Hermetic storage such as hermetic bags and metallic silos operate on the principle of modified environments with high barrier properties against gaseous and moisture exchange [32], limiting mold growth [33,34]. Hermetic storage systems have been reported to increase carbon dioxide and reduce oxygen levels in storage to levels inhibitory to mold growth and aflatoxin contamination [6,35,36]. The increases in mold infection observed in hermetic bag storage in the sixth month could be attributed to the fact that the modified gas conditions (increased carbon dioxide and lowered oxygen levels) are not maintained over time [6]. ...
... At six months of storage, 93.54%, 21.67% and 16.12% of the samples of grain stored in the polypropylene bags, hermetic bags and metallic silos, respectively had above 10 ppb aflatoxin contamination. These findings concur with data from studies conducted in Kenya [6] and West Africa [35] that reported significant increase in mold infection and aflatoxin levels in produce stored in woven polypropylene bags. Lower aflatoxin levels in hermetic storage can be attributed to the high barrier properties, gaseous composition and modification that is considered in their development and use [6]. ...
... Modification of the environment during hermetic storage is attributed to aerobic metabolism that is influenced by elements such as grain moisture content, insect population, fungal inocula, quality of the grain and gas-tightness [32]. Hermetic storage systems have been reported to increase carbon dioxide and reduce oxygen levels in storage to levels inhibitory to mold growth and aflatoxin contamination [6,35]. ...
... Maize (Zea mays L.) is a staple food in Africa and its contribution to food and income security of households of smallholder farmers is substantial [35], [7]. In Ghana, maize is produced on about one million hectares of land and accounts for 50-60% of total cereal production. ...
... Respiration of grains, insects and other living organisms in the bag depletes oxygen and increases carbon dioxide to levels that inhibit growth and development [27]. Storage of grains in hermetic bags to minimize losses is being promoted in sub-Saharan Africa [7], [13]. Several workers [22], [4], [5], [6] have worked on hermetic storage bags for the protection of various commodities against storage insect pests in Ghana but the investigation have concentrated on the Triple-Layer hermetic storage bags. ...
... Results of this study are similar to those of [31] who reported strong correlations between number of holes observed in hermetic grain bags and insect numbers, mortality rate and losses, and concluded that holes in the liner negatively affected the effectiveness of hermetic storage bags. Prostephanus truncatus is known to have extraordinary capabilities to bore through different kinds of materials including plastics [8], [7]. According to [32] an ideal hermetic storage structure including an inner liner should have high integrity in terms of structural strength and should be air-tight or provide reasonable impenetrability in order to minimize or eliminate the effects of ambient atmosphere on insect activities, and that these intrinsic qualities that assure effective storage differ with product type. ...
Article
High post-harvest loss of maize due to stored product insect pests remains a food security challenge in Ghana. This field study evaluated the effectiveness of a novel technology, ZeroFly® Hermetic storage bags with different inner liners, to protect maize against infestation by Sitophilus zeamais Motschulsky and Prostephanus truncatus Horn. The study was carried out in the. Maize pre-fumigated with Phostoxin® was stored in 50-kg ZeroFly® Hermetic storage bags. Experimental treatments were 20-µm High Density Polyethylene (HDPE) inner liner with oxygen absorber, 20-µm HDPE inner liner without oxygen absorber, 80-µm Polyester and Ethylene Vinyl Alcohol (EVOH) inner liner with oxygen absorber, 80-µm EVOH inner liner without oxygen absorber, 50-µm Charter NEX high barrier inner liner with oxygen absorber, 50-µm Charter NEX medium barrier inner liner with oxygen absorber, and untreated maize-filled 50-kg polypropylene bags without oxygen absorber (control). Maize-filled 50-kg polypropylene bags without oxygen absorber were used as Control. The percent insect damaged kernels on number basis (%IDKnb) recorded in the 20-µm HDPE liners and polypropylene bags were > 15% compared to < 1.8% recorded in the other treatments. Weight losses in the 80-µm EVOH and 50-µm Charter NEX high and medium barrier liners were < 0.35%. Aflatoxin levels were below the 15 ppb threshold. The results of the study showed that, ZeroFly® Hermetic storage bags with 80-µm EVOH inner liner and 50-µm Charter NEX high and medium barrier inner liners protected stored maize against S. zeamais and P. truncatus over the 6-month storage period.
... The results of different field trials for maize were used to estimate the benefits of the hermetic bags for food security, GHG emissions and the economic outlook in different Sub-Saharan countries. The average effects of hermetic bags and the use of insecticides on PHL reduction during field trials involving stored maize grain were calculated based on data from five different field studies of the storage of maize in Sub-Saharan Africa: Baoua et al. (2014), Likhayo et al. (2016), Ndegwa et al. (2016), Ng'ang'a et al. (2016b, and Mlambo et al. (2017). Table 1 shows some of the characteristics of these studies. ...
... A striking reduction in market value was observed for the use of the standard bags during the first 150 days of storage, with <5% of the volume classed as being of a good quality, and >90% assessed as being of an unmarketable quality. The slight improvement in quality observed between 150 and 200 days of storage was due to a number of good quality samples in this period coming from the study of Baoua et al. (Baoua et al., 2014), which were explained by a low infestation rate and very dry product. Storage in standard ...
... This becomes even more relevant if the lifespan of the bags is reduced from 3 years to 1 year. After one harvest, the hermetic bags showed already some holes in the liners, mostly made by the insects (De Groote et al., 2013;Baoua et al., 2014). Although hermetic bags are still functional with a small number of holes in the liner, they will be more vulnerable to disruptions, thereby losing their efficiency over time. ...
Article
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During storage, cereals and legumes are vulnerable to insects, rodents, and fungi, which can cause loss of weight, damage or discoloration of products, and/or toxin formation. Hermetic bags can prevent excessive insect infestation, and toxin formation. This paper presents an analysis of the effects of hermetic bags for the storage of maize on food loss reduction by insects and on net greenhouse gas (GHG) emissions, based on practical data from field trials. Their economic feasibility, by optimizing the total income in markets with different price seasonalities in different Sub-Saharan African countries, is analyzed. The data of five field trials were combined and put in classes of 50 days of increasing storage time to get a realistic loss of produce during storage using regular bags (with or without the use of pesticides) and hermetic bags. The maize for storage trials were used as is, bought locally or used direct from the field. Scenario studies with standard storage, standard storage combined with pesticides and hermetic bag storage show significant losses by insects after 100 storage days for standard and standard with pesticides storage, whereas with hermetic bags, product losses are kept to a minimum of 2%. The economic analysis shows less clear-cut outcomes: the interventions' effectiveness depends largely on the rate of seasonal price fluctuation of the commodity. For farmers' personal consumption, when the quality is less critical, the use of hermetic bags is only more economical compared with other methods of storage for produce kept over 100 days. Since the quality of maize is well-preserved by the hermetic bag, the return on the investment is shorter when the maize is sold at the market. However, for countries with a low seasonal price gap, the investment cannot be recouped. As the use of hermetic bags is a good intervention for preventing food loss, it is best promoted not only for providing direct profits to farmers but also for health benefits, as bag use implies a lower need for pesticides and a possible reduction in aflatoxin intake.
... The results are in line with the results of Yakubu et al. 2010, who recorded Effect of Hermetic Storage on Seed Quality Maintenance of Dolichos Bean [Lablab purpureus (L.) var Typicus Prain] that there is higher mortality of maize weevil, S. zeamais, in triple layer PICS bags at low temperature and low seed moisture level as they created hypoxia (depleted oxygen levels) conditions sooner compared to the seeds stored at high temperatures and moisture level. Baoua et al. 2014 compared the germination percentage after storing Bambara groundnut (Vigna subterranean) slightly infested with C. maculatus and C. subinotatus for a period of seven months in triple layer bags and woven polypropylene bags and observed the germination percentage was found to be 34.8% in polypropylene bag and 89.3% in triple layer bags. ...
... They compared the effectiveness of triple layer bags with that of jute and polythene bags against maize weevil, S. zeamais and observed highest percent mortality of S. zeamais, seed germination recorded in triple layer bags and increased level of seed damage, weight loss in jute bags followed by polythene bags. Mortality 95-100% of storages pests of maize P. truncatus, S. zeamais with no significant loss weight and a germination of 90.5% when stored in triple layer plastic bags but higher weight loss, poor mortality of storage insects and reduction in germination percentage of maize stored for a period of 6.5 months in woven polypropylene bags was recorded by Baoua et al. 2014. ...
Article
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Background: Dolichos bean is one of the important vegetable legume crops. During storage, protection of seed from bruchid attack is a major problem worldwide. Once the bruchid attacks, the extent of damage could be up to 100%, leading to both quantitative and qualitative loss by making it unfit for consumption. Existing traditional methods are less effective or impractical and the use of chemical methods can be harmful to the farmers and consumers. So, there is urgent need of hermetic storage method for seed quality maintenance. Keeping in view, the present study was carried out to investigate on hermetic storage practices for seed quality maintenance. Methods: Triple-layer PICS technology, a chemical-free hermetic storage was evaluated for storage of dolichos bean to moisture content, germination and quality. Four different types of storage bags viz., jute bags, polythene bags, triple layer PICS bags and jute bags treated with chlorpyrifos were used for evaluating their efficacy in managing dolichos bean seed attributes. The data on various parameters pertaining to seed characteristics and changes in biochemical composition of dolichos bean seeds stored in different bags was recorded at every two month intervals for 3 times (2,4, and 6 months) by using standard protocols. Complete Randomized Design (CRD) (Snedecor and Cochran, 1967) was used for the data analysis. The data was subjected to statistical analysis as per the methods suggested by Panse and Sukhatme (1985). Result: Results on moisture content showed that, in case of storage in PICS bags, there was no decrease in seed moisture content at 2, 4 and 6 months respectively and germination percent in triple-layer PICS bag at 2, 4 and 6 months storage was highest among all bag types. Test weight (g), protein content (%) and carbohydrate content (%) at 2, 4 and 6 months storage respectively were higher in triple layer PICS bag. The mean fat content recorded was highest in jute bag (1.25%) and lowest in triple layer PICS bag (0.63%). Our study concludes that the triple layer PICS bags hermetic technology is efficient in managing maintaining same level of moisture content percent, germination percent and test weight compared to other bags over 3 different periods of storage. The triple layer PICS bags are also highly useful for retaining carbohydrate percent and protein percent at almost the same levels compared to initial values.
... Once the PICS bag is packed with grain and sealed, the metabolic processes of living organisms within the bag deplete the oxygen accessible, and the O 2 will produce in small amounts (less than 5%) (Murdock et al., 2012). The low O 2 amount retard the growth, reproduction, and existence of insects and pathogens (Baoua et al., 2014;Tubbs et al., 2016). ...
... PICS bags decreased the movement of O 2 and restricted the release of CO 2 , which may inhibit the production of insects in stored grain (Murdock et al., 2012). Baoua et al. (2014) used PICS bag to store an infested maize and found that 53% of maize had aflatoxin contamination rates above 20 ppm. Moreover, the authors added that maize in PICS bags appeared to have less aggregation than those in woven bags. ...
Chapter
Food grains such as cereals, legumes, and oilseeds are important food crops that contribute to most of the world’s staple food, especially in developing countries. However, up to ~ 70% of food grains produced can be lost during postharvest management activities such as storage, transport, milling, drying, threshing, etc. The current challenge is to develop sustainable ways to reduce postharvest losses of food grains while increasing production. Several technological advancements have been made in recent years. In this chapter, the current state of the art of various advanced technologies used to reduce food grain losses during drying, milling, sorting, packaging, and storage is discussed. A future outlook to further develop these advances to drastically reduce the postharvest losses of food grains is also elucidated. Future research should be directed towards intensifying the use of smart sensors, IoT resources, and digital twins to enhance postharvest management practices. This book chapter provides valuable insight into sustainable technologies to improve postharvest management practices and reduce postharvest losses of food grains.
... In shelled maize stored in hermetic bags, Njoroge et al. (2014) found that during a six month storage period, population growth of P. truncatus was notably delayed, while seed germination remained high. Extensive studies in different parts of Africa have confirmed the efficacy of hermetic bags for the control of P. truncatus under a wide range of conditions and scenarios (Baoua et al., 2014;Hell et al., 2014;Njoroge et al., 2014;Nwaubani et al., 2020). Nwaubani et al. (2020) found that hermetic bags were superior to other control methods on maize, not only for P. truncatus, but also for other major insect species, such as S. zeamais and psocids. ...
... The ability of this species to easily penetrate plastics should be seriously considered when designing IPM programs, since it can negatively affect hermetic storage based on plastic bags. Other studies confirm the importance of this consideration, showing hermetic bags may allow P. truncatus to continue causing grain damage in bagged-stored maize, and they may falsely provide the impression that hermetic storage is effective against the species when they are not (Baoua et al., 2014;Chigoverah and Mvumi, 2018;Ognakossan et al., 2013). Further, Chigoverah and Mvumi (2018) compared four different hermetic plastic bag types and reported that all four were susceptible to penetration by P. truncatus, confirming its ability to penetrate plastics, regardless of their specific type. ...
Article
Full-text available
The invasive larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae), originating from Meso-America, is a devastating stored product pest of maize (Zea mays L.) and cassava (Manihot esculenta). This species can destroy up to 40% of stored maize within four months. Despite four decades of research, P. truncatus has spread throughout Africa, while decimating maize and cassava production. Given the continuing problems with P. truncatus, the likelihood for its continued range expansion under climate change, and its status as a species of concern in many countries, the objective of this review was to provide an updated and comprehensive freely accessible record of the distribution and spread, biology, development, and ecology, host preferences, chemical ecology, detection, and monitoring, and management of P. truncatus. We conducted a search of the literature from 1911 to 2021 using Google Scholar and Web of Science to find all papers related to key search terms. We found that P. truncatus has been recorded in 36 countries across the globe, including 21 now in Africa. A recent predictive model found that the insect has been limited to tropical and subtropical regions but could likely spread to temperate regions as temperatures rise with climate change. Conspecifics respond to their two component, male-produced aggregation pheromone early after eclosion, but quickly switch to other cues as older adults. At close-range, P. truncatus may use food cues, but host volatiles are not involved in long-range host finding of commodities. Research on managing P. truncatus has mostly focused on chemical control to the detriment of other tactics, with the most promising tactic likely to be the different hermetic storage technologies. Many outstanding areas of basic behavior and ecology remain to be assessed for P. truncatus. We highlight specific areas that should be prioritized for further work in order to better manage and reduce the impact of this invasive insect pest.
... Previous works have underlined this observation in grain moisture between woven (polypropylene) bags or hermetic bags. Experiments conducted using the hermetically sealed Purdue Improved Crop Storage (PICS) bags for maize storage, grain moisture content fluctuated in control polypropylene bags, but had no significant changes in PICS bags (Baoua et al., 2014;Martin et al., 2015;Afzal et al., 2017;Williams et al., 2017;Kharel et al., 2018). The authors suggested that the ambient humidity over the storage period together with the porous nature of the woven bags may explain this fluctuation. ...
... However, considering the number of insects per kilogram of stored grain, we estimate that the use of the hermetic bags for longer storage intervals might have gradually eliminated insect populations once sufficient numbers were obtained to consume all available O 2 . Previous studies conducted using PICS bags, grain was stored for 6 months or longer before the presence of living insects were counted (Baoua et al., 2014;Martin et al., 2015;Williams et al., 2017). In the current study, a significantly shorter period of storage time was used and it is possible that increased storage time could have resulted in significant fewer live T. granarium. ...
Article
Long-lasting insecticide treated netting (LLIN) has a number of potential uses for the control of insect pests. Using such netting, stored products may be protected from insects including the khapra beetle (Trogoderma granarium Everts, Coleoptera: Dermestidae) a widespread pest of many agricultural commodities. Here we first examined whether brief exposures of larvae to LLIN, for less than 30 min, decreased the chance of eventual adult emergence compared to larvae exposed on untreated netting. Next, we observed the responses of larvae that were either not exposed to any netting, exposed to untreated netting, or exposed to LLIN for 10 min and then placed in a wind tunnel and monitored for movement toward a stimulus. The wind-tunnel assay was performed either with or without a lure containing kairomones and pheromones known to be attractive to larvae of this species. There was little effect of the LLIN on adult emergence of exposed larvae. However, there were interacting effects of untreated netting and LLIN relating to thigmotaxis and anemotaxis. Larvae not exposed to netting showed increased likelihood of walking upwind if the semiochemical lure was provided, as expected. A similar pattern was observed when the untreated netting was used, but the larvae became more likely to remain stationary in the assay after acclimating to the net. When LLIN was used, the larvae became more likely to move and there was a baseline increase in the likelihood of moving upwind. However, upwind walking was no longer related to semiochemical presentation. These observations suggest that particular care should be used in relation to the airflow patterns and semiochemical landscape of the warehouse settings in which LLIN is deployed.
... Previous works have underlined this observation in grain moisture between woven (polypropylene) bags or hermetic bags. Experiments conducted using the hermetically sealed Purdue Improved Crop Storage (PICS) bags for maize storage, grain moisture content fluctuated in control polypropylene bags, but had no significant changes in PICS bags (Baoua et al., 2014;Martin et al., 2015;Afzal et al., 2017;Williams et al., 2017;Kharel et al., 2018). The authors suggested that the ambient humidity over the storage period together with the porous nature of the woven bags may explain this fluctuation. ...
... However, considering the number of insects per kilogram of stored grain, we estimate that the use of the hermetic bags for longer storage intervals might have gradually eliminated insect populations once sufficient numbers were obtained to consume all available O 2 . Previous studies conducted using PICS bags, grain was stored for 6 months or longer before the presence of living insects were counted (Baoua et al., 2014;Martin et al., 2015;Williams et al., 2017). In the current study, a significantly shorter period of storage time was used and it is possible that increased storage time could have resulted in significant fewer live T. granarium. ...
Article
The khapra beetle, Trogoderma granarium (Everts), is a highly destructive stored product insect that presents a significant threat to stored bagged grain. Hermetic packaging is designed to maintain the quality and safety of stored grain, while continually protecting the grain from insect infestations during storage. The objective of this research was to evaluate a prototype deltamethrin, all-in-one treated hermetic bag on contact efficacy, larval mobility, and the control of T. granarium in artificially infested wheat. The insecticidal activity of the deltamethrin-treated packaging was tested against larvae and adults of T. granarium through contact bioassays. There was a significant reduction in responsive adults after 5 day and >86% of larvae were unresponsive after 9 d of exposure on the treated bag. Trogoderma granarium movement toward a food bait was <10% after a 24 h exposure on the treated bag compared to ~45% of larvae on untreated bag. Lots of 15 kg of wheat were artificially infested with 100 T. granarium larvae and placed inside treated and untreated storage bags, sealed, and stored in a semi-field warehouse, and observed after 2, 6, and 8-weeks for T. granarium survival and grain quality attributes. The weight and number of insect damaged kernels was lower across all storage intervals for grain held in the treated bags, as compared with control bags. Live adult T. granarium were observed at 2-weeks in treated and untreated bags, but there were no live adults observed after 8-weeks of storage in both bags. The new prototype hermetic bags maintained positive grain qualities, however more information on the hermetic parameters are needed to understand how some individuals survived.
... Compton et al., 0.6 per cent to 1 per cent reduction in the value of maize is due to insect infestation [32,36]. ...
... In order to promote the adaptability among customers, it is important to technical effectiveness, and limitation of usefulness of new approach. Natural insecticides, chemical fumigation and hermetic storage can help to reduce losses [32,33]. In warehouses, super and hypermarkets, technological advanced interventions and storage structures can reduce losses [9,24,34]. ...
Article
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Cereals are the main food on this earth planet. The losses of produced cereals are very big issue globally. Post harvest losses are more severe in developing countries at food chain level and very high at retailing and consumption level in developed countries. Due to high post harvest loss, major part of African countries suffers with malnutrition. Ministry of Food Processing in 2007 reported that agriculture produce of 580 billion rupees is wasted every year due to post harvest losses. In developing countries both quality and quantity losses are the main issue of post harvest crops. These are needed to develop advance and cost effective storage methods to reduce post harvest losses. It is also important to use IoT in supply chain, hermetic storage techniques, synthetic insecticides, pesticides, fungicides and natural fumigants to control insect pest attack on stored grains. With all these integrated precise techniques we can minimise post harvest losses at both supply chain processes and consumption level and can fulfil the increase demand of cereals around the world.
... The expansion of soybean cultivation in the world necessitates the improvement of agricultural production processes with the use of precision technologies, which are associated with genetic improvements and seed conservation, thereby creating the need for the production of seeds with better physiological and sanitary qualities [1]. Among other factors, the physiological quality of the seeds depends on production management and the conduct of post-harvest operations [2]. ...
... Storage is an important post-harvest stage, the main objective of which is to conserve seed quality by reducing the speed and intensity of the deterioration process as much as possible [2][3][4][5]. When storage conditions are not adequate, soybean seeds suffer viability losses owing to the increased metabolic activity that promotes a reduction in their physiological quality [6,7]. ...
Article
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Different regions have different environmental conditions, which may be unfavorable for the preservation of the quality of stored soybean seeds over time. Thus, it is necessary to adopt specific technologies to control the storage environment conditions. Big raffia bags are widely used for the storage of soybean seeds, however these consist of a porous, permeable material that allows the exchange of gases between the packaging and the storage environment. In an effort to find a solution to this problem, in this study we evaluated low cost big bag coating alternatives, in order to minimize the effects of temperature and inter-granular humidity on stored seeds. Thus, the aim of this work was to evaluate the quality of soybean cultivars subjected to different temperature and storage duration conditions and stored in raffia bags with or without internal coating. We used a completely randomized, three-factor (10 × 6 × 5) experimental design. We assessed 10 soybean cultivars, six storage environments, and five evaluation periods. Our results showed that seeds of the M-SOY 8866, M7110 IPRO, CD 2737 RR, and BMX DESAFIO 8473 RSF soybean cultivars preserved their physiological quality better in different storage environments. The storage duration had a cumulative effect on the negative factors that favor the deterioration of the quality of the stored seeds. The storage temperature was the main factor that affected the physiological quality of the stored seeds. The use of coated packaging was beneficial in preserving the physiological quality of stored soybean seeds; however, its effect was greater at ambient temperature than in a cold environment. The best storage environment for the preservation of the quality of the seeds was characterized by 10˚C temperature conditions and the use of coated packaging, while the worst storage environment was characterized by ambient temperature conditions without the use of coated packaging. Thus, it was concluded that the use of coatings in raffia big bags can be an alternative for maintaining the quality of seeds of different soybean cultivars during storage in seed processing units.
... A study by Hell et al. (2014) reported that the bag has two-layers that create low air permeability thereby causing insects to die. Similar results were reported by (Baoua et al., 2014) that PICS bags could be used to safeguard against rodent pests' damage to stored grains. Ng'ang'a et al. (2016) reported that PICS bags work well when oxygen, carbon dioxide, temperature and humidity are monitored under farmers storage conditions. ...
... This coincides with the findings of (Mulungu et al., 2006;Abass et al., 2014) who reported that grain storage losses are attributed to factors such as temperatures, humidity and the invasion of rodents, insects and other pests. Rats were seen to be the most problematic in storage structures in nangoma area and this could be attributed to smell, taste and crop variety of the stored crop (Tefera et al., 2011;Baoua et al., 2014;Abass et al., 2014). The results from the current study showed that the estimated weight grain loss in storage facility from harvest upto consumption ranged from 0-25%. ...
Preprint
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Farmer-based in storage crop protection methods against rodents and other pests in Mumbwa, Zambia.
... Hermetic bags application has been promoted in the Sub-Sahara region over the past few decades for the safe storage of maize and other vulnerable crops (Baoua et al., 2014). The hermetic bags are made of plastic with high thickness and low permeability to atmospheric gases. ...
... This study resulted that the storage of a wheat commodity in polypropylene bags suffers from high economic weight loss, grain damages, and population buildup resulting in quantitative and qualitative losses which could be the reason for low prices in the market. These results are in agreement with previous studies on the efficacy of the hermetic bag for stored grain insect pest management (Murdock et al., 2012;Baoua et al., 2014;Lane and Charles, 2017). The temperature inside hermetic bag fluctuated as per previous reports but relative humidity gained equilibrium inside hermetic bag in contrast to earlier studies (Lane and Charles, 2017;Baributsa et al., 2020). ...
Article
Wheat Triticum aestivum (L.) is an important staple food in Pakistan. However, post-harvest losses either quantitatively (weight loss, commercial loss) or qualitatively (changed appearance and lower nutritional value) by various stored grains insect pests, and environmental conditions are major concern. This study was aimed to evaluate the efficacy of hermetic and polypropylene bags in protection against insect pests and maintaining grain quality under different environmental conditions. Results showed that grain moisture fluctuated in polypropylene bags with variations in relative humidity in the environment, while in the hermetic bag it was decreased in all three sites. Relative humidity reduced in hermetic bags on all three sites and became constant within a week for the rest of the period while increased in polypropylene bags due to environmental humidity and insect infestation. However, a great variation in temperature fluctuation in both bags on all three sites was recorded. Germination remained unaffected in hermetic bags while a significant reduction (35%) occurred in polypropylene bags. Insects were unable to damage grains inside hermetic bags while grain weight loss (14.97-15.53%), damaged grains (27.43-30.93%), and reduced germination (26-27.5%) were recorded in polypropylene bags due to infestation of insect pests (Tribolium castaneum (Herbst), and Sitophilus granarius L. and S. oryzae L). Moreover, no aflatoxins were recorded in both bags at all three sites. Our findings suggest that in Pakistan, it is technically feasible to control insect pests of storage by using hermetic storage bags.
... Several other scholars have demonstrated the protective action of HS against the damaging effects of insect-induced grain damage and weight loss in stored grains (Atta et al., 2020;Baoua et al., 2014a;Baoua et al., 2012;Somavat et al., 2017;Yakubu et al., 2011). Table 2 shows the comparison of HS against traditional storage technologies on grain damage and weight loss. ...
... The moisture content of stored grains is the most important physical factor in grain deterioration since it favors the growth and proliferation of toxigenic molds (Sawant et al., 2012). When stored under non-hermetic conditions, grains absorb and lose moisture in humid conditions and dryer environments, respectively, until the attainment of equilibrium moisture content (Baoua et al., 2014a;Williams et al., 2014). Apart from exposure to varying external relative humidity levels, grains stored in non-hermetic devices may also gain moisture due to high insect activity and heavy fungal growth resulting from the breakdown of organic matter to yield CO 2 , moisture, and heat Njoroge et al., 2014). ...
Article
The purpose of this study was to review the different hermetic storage (HS) systems used in Sub-Saharan Africa (SSA) and their effectiveness against the agents of storage quality deterioration. Relevant studies on grain HS in SSA conducted in the past two decades for effectiveness against the agents of storage losses are reviewed. Specifically, the study comprehensively reviewed the effectiveness of HS technologies against insect-induced damage and weight loss, seed germination, insect infestation, and mold and mycotoxin contamination. Traditional grain storage methods and HS technologies used in SSA are reviewed, including those suitable for smallholder farmers and traders. Future developments and modifications to HS are also discussed. Most grain HS studies are carried out in SSA where post-harvest storage losses are considered one of the world’s largest. Scholarly studies compared the performance of HS against traditional technologies for storage periods of up to 7 months and a few extending to 1 year or more. Commonly studied HS technologies include hermetic layered bags and grain silos. In general, HS offers superior protection against the agents of grain deterioration for long-term storage compared to conventional storage technologies. HS technologies are highly effective in protecting stored grains from quantitative and qualitative storage losses and thus guarantee that stored grains can attract better prices and are safe and nutritious to the consumer. Keywords: Post-harvest losses, Grain storage, Hermetic storage, Smallholder farmers, Sub-Saharan Africa
... Abdoulaye et al. (2016) report that more than 75% of farmers in Ghana, Tanzania, and Benin identified insects as the major cause for PHL, while most farmers in Ethiopia, Uganda, and Nigeria complained about rodents and moisture as main causes for PHL. Finally, Compton et al. (1997) and Baoua et al. (2014) show that each percentage point of insect infestation results in between 0.6% and 1% depreciation in the value of maize. Certain climatic conditions, especially heat and moisture, tend to increase the prevalence of insects, pests and other bio-deterioration factors, especially when proper storage and transportation structures that control temperature and humidity are lacking. ...
... Abdoulaye et al. (2016) report that more than 75 percent of farmers in Ghana, Tanzania, and Benin identified insects as the major cause for PHL, while most farmers in Ethiopia, Uganda, and Nigeria reported rodents and moisture as the main causes for PHL. Finally, Compton et al. (1997) and Baoua et al. (2014) show that each percentage point of insect infestation results in between 0.6 percent and 1 percent depreciation in the value of maize. Certain climatic conditions, especially heat and moisture, tend to increase the prevalence of insects, pests, and other biodeterioration factors, especially when proper storage and transportation structures that control temperature and humidity are lacking. ...
... A recusa de lotes de sementes deve-se principalmente à presença de impurezas. Baoua et al. (2014) examinaram a cadeia de suprimentos do milho, que é uma das principais culturas alimentares da África Ocidental. Pragas presentes no armazenamento são as principais restrições na cadeia de suprimentos do milho, com perdas chegando a 30%. ...
Conference Paper
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Um terço dos alimentos que são produzidos para o consumo humano é perdido ou desperdiçado a cada ano em toda a cadeia de suprimentos agroalimentar. O desperdício está relacionado a diferentes fatores, como: nível de renda, urbanização e crescimento econômico. Em países emergentes, as perdas e desperdícios ocorrem principalmente nas fases de pós-colheita e processamento; e nos países desenvolvidos, acontecem geralmente durante o consumo. Este estudo teve como objetivo identificar as principais causas das perdas em cadeias de suprimentos agroalimentares, focando as operações de transporte e armazenagem. Foi realizada uma Revisão Sistemática da Literatura na base de dados SCOPUS, permitindo a análise de 26 artigos sobre o tema. Os estudos, em grande parte, focam em países emergentes, sendo as principais causas das perdas a infraestrutura de transporte precária e a refrigeração inadequada. Com a identificação das causas, este estudo oferece insights de intervenções para a diminuição das perdas de alimentos.
... 1 Innovation and Technology adoption Mlambo et al., 2017;Williams et al., 2017;Krska et al., 2016;Asefi et al., 2015;Yusuf e He, 2011;Shao et al., 2015;Jia e He, 2015;Zhang et al., 2014;Liang et al., 2013;Kong et al., 2009;Khatchatourian e Binelo, 2008;Ward e Davis, 2013;Nascimento et al., 2009;Andrighetto et al., 2008;Marques Neto e Silva, 2011. Othira et al., 2009Stathers et al., 2008;Wang et al., 2014;Zhang et al., 2014;Chigoverah e Brighton, 2016;Baoua et al., 2014;Conteh et al., 2015;Mwebaze e Mugisha, 2011; Dissanayake e Jain, 2010 24 2 Prevention against pests and insects Dowell e Dowell, 2017;Nhamucho et al.,2017;Danso et al., 2017;Baoua et al., 2015;Musundire et al., 2015;Quirino et al., 2013;Ntonifor et al., 2011;Rani e Devanand, 2011;Zhang e Mao, 2009 9 3 Control and management of grain quality Coradi et al., 2016;Zhang et al., 2014;Furlan;Morozini, 2013;Santos et al., 2012;Nascimento e Queiroz, 2011;Catão et al., 2010;Costa et al., 2010;Gutkoski et al., 2009 8 4 Storage techniques Mendoza et al., 2017;Likhayo et al., 2016;Yang et al., 2016;Di Domenico et al., 2016;Sahu et al., 2015;Wu et al., 2014 6 5 Control of losses Mwangiab et al., 2017;Gao et al., 2016;Karunasagar e Karunasagar, 2016;Dong et al., 2014;4 6 Food Security Monda e Alakonya, 2016; Zhai et al., 2015;Domenico et al., 2015;Jayas, 2012 4 7 Implementation of storage facilities and investments Bocca;Galves, 2016;Nourbakhsh et al., 2016;Machado et al., 2015 3 8 Quality of grain stored for feed Dafei et al., 2017;Carvalho et al., 2009 2 9 Static capacity and logistics Nouhoheflin et al., 2017;Silva Neto et al., Four subcategories (SC) emerged from the major category Innovation and technology adoption (Frame 2). The subcategories were referred to (baptized) as (a) SC1: Technology and innovation related to food security (6), (b) SC2: Technology and innovation related to control and prevention against pests and insects (7), (c) SC3: Technology and innovation about loss and waste prevention (4), (d) SC4: Technology and innovation related to specific topics and case studies (6). ...
Article
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Research related to grain storage spans to a wide range of aspects. It is a relevant topic for many sectors of the value chain. Studies have been developed to reduce grain losses in terms of food security and food safety. This comprises the need for innovation in terms of technology and logistics. Surprisingly, major players on grain production and exportation, such as Brazil, still struggle to guarantee the proper static storage capacity recommended by The United Nations (FAO). Because grain storage is crucial in the global food supply chain, we aimed to deliver descriptive statistics, identifying trends in literature that may deliver valuable diagnosis and nurture innovative research on the field. Our approach was based on performing quantitative and qualitative appreciation of the scientific production on grain storage between 2008 and 2017. A step by step protocol was made available to allow traceability of all criteria adopted during the workflow. The methodological procedures enabled clustering of scientific production according to the similarity of content and discrimination of scientific production according to several criteria (i.e., peer reviewed journals, universities, countries). Also, an explicit demonstration of networking among academics enabled the identification of pathways and alternative strategies towards innovation in the field. Overall, bibliometric and content analysis of the published manuscripts revealed trends, gaps and legible perspectives for academics interested in the field of grain storage.
... OGNAKOSSAN (2013) ont observé des cas où P. truncatus a perforé des sacs hermétiques contenant des grains de maïs après 120 jours de stockage en laboratoire. D'autres auteurs ont également signalé des perforations provoquées par des insectes sur des sacs de type PICS contenant du maïs en Afrique de l'Ouest après 6,5 mois de stockage(BAOUA et al., 2014a). SelonMARTIN et al. (2015b) l'augmentation du taux d'oxygène dans les doublures (sachets) en plastiques hermétiques contenant des grains infestés est proportionnel aux perforations causées par les insectes. ...
Article
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Cette étude vise à comparer les performances de sacs à triple fond utilisés au Burkina Faso pour la conservation des grains de maïs. Quatre types de sacs à triple fond (PICS, ETONG, PAPSA, et FAO) et un sac en polypropylène (témoin) ont été évalués. Cette évaluation a consisté à conditionner dans chaque type de sacs, 25 kg de grains de maïs infestés artificiellement avec 100 individus adultes de P. truncatus durant six mois dans les conditions ambiantes de laboratoire. Pour chaque type de sacs, 4 répétitions sont constituées. Les résultats montrent qu’au terme de cette période, 92 à 98% des individus adultes de P. truncatus étaient morts dans les sacs à triple fond comparativement au témoin (en polypropylène). Dans les sacs à triple fond, le taux de perforation des grains (7 à 16%), le taux de pertes en poids (1 à 2%) et le poids des débris farineux (1 à 4%) occasionnées par les insectes ne diffèrent pas significativement entre eux mais sont inférieurs à ceux observés dans les sacs en polypropylène. Les perforations des sachets interne et externe par P. truncatus n’ont pas varié dans les sacs à triple fond. Comparé à la situation initiale, le taux de germination des grains de maïs a baisé significativement de 22 à 33% dans les sacs de type FAO, ETONG et PICS qui ne diffèrent pas entre eux et de 64% dans les sacs PAPSA et les sacs sacs en polypropylène qui ne diffèrent pas aussi entre eux.
... In addition, the combination of plants and the triple bagging system would inhibit the metabolism of insects and molds. They can also be explained by both the reduction of oxygen (O2) and the insecticidal and fungicidal activity of plants [25,26]. This antifungal activity is due to the presence of mono and sesquiterpene compounds in these plants [27]. ...
Article
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In Côte d’Ivoire, maize plays an essential role as subsistence, commercial and socio-cultural culture. To consume good quality corn, it is necessary to preserve the sanitary quality through a good storage method. The aim of study was to evaluate sanitary quality of stored maize in triple bags containing plants biopesticides. Maize grains were collected in March 2016 in the north of Côte d’Ivoire. The fresh leaves of Lippia multiflora and Hyptis suaveolens were collected and dried in sunlight for 7 days in the center of Côte d'Ivoire. Triple bags were bought in Abidjan market. All this material was sent to the Laboratory of Biochemistry and Food Sciences, Félix Houphouët-Boigny University, Côte d’Ivoire, to perform the experiment. A central composite design was used for sample constitution. Ten treatments were obtained for the experimentation. The first treatment was conservation of 50 kg of maize grain in a polypropylene bag. The second treatment was conservation of 50 kg of maize grain in a triple bag. The other eight treatments were carried out with PICS bags each containing 50 kg of maize grain and different proportions of chopped leaves Lippia multiflora and Hyptis suaveolens. Thus, a control group with polypropylene bag (TPPB0), a control group in triple bag without biopesticides (TPB0) and 8 experimental lots of triple bags noted TB1 containing 0.625kg L. multiflora and 0.625kg H. suaveolens, TB2 with 0.40 kg of L. multiflora and 1.60 kg of H. suaveolens, TB3 with 1.60 kg of L. multiflora and 0.40 kg of H. suaveolens, TB4 with 0.10 kg of L. multiflora and 0.40 kg of H. suaveolens, TB5 with 0.40 kg of L. multiflora and 0.10 kg of H. suaveolens, TB6 with 2.5 kg of L. multiflora and 2.5 kg of H. suaveolens, TB7 with 1.25 kg of L. multiflora and TB8 with 1.25 kg of H. suaveolens have been used. The contents of moisture, water activity, aflatoxin B1 (AFB1), ochratoxin A (OTA), fuminosin B1 (FB1) and zearalenone (ZEA) were studied. The levels of AFB1, OTA, FB1 and ZEA resulted from maize grains treated with biopesticides were significantly lower than those recorded with untreated maize of control bags. The results show AFB1 levels (from 4.17 ± 0.05 to 5.15 ± 0.06 μg/kg), OTA levels (from to 4.58 ± 0.25 to 6.10 ± 0.01 μg/kg), FB1 levels (from 4.96 ± 0.07 μg/kg to 7.42 ± 0.06 μg/kg) and ZEA levels (from 4.66 ± 0.10 μg/kg to 8.78 ± 0.14 μg/kg). Maize samples stored in triple bagged bags with different proportions of biopesticide were significantly lower than those recorded in the polypropylene woven sample bag (TPPB0) and in the triple bagged control bag (TPB0) during the storage period. Storage of maize grains in triple bags with the leaves of L. multiflora and H. suaveolens appears as a method of effective and inexpensive conservation to ensure the sanitary quality of maize. This inexpensive and easy-to-use treatment should be popularized among farmers.
... Losses for beans stored on-farm without any protection can be significant (Kamanula et al., 2010) . Risks arising during storage can be somewhat managed (e.g. with chemicals or hermetic storage bags; Baoua et al., 2014) but such management may incur additional labor or monetary costs. The upshot is that farmers may prefer transferring risk, leaving traders to bear the risks of extended seed storage (e.g., CRS and Partners, 2006 ). ...
Article
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Seed system interventions can spur agricultural growth and often focus on accelerating delivery of new varieties and good seed. The driving logic is that such modest investments can bring key gains, even to the poor and in challenging contexts. This article focuses on Africa and legumes, crops key for nutrition, soil enhancement, resilience to climate stress and rapid income generation. The default design for seed sector development, based on maize, proves inadequate for moving legume varieties and seed to smallholder customers. The article draws from a large dataset including 10,209 transactions from nine African countries. Findings show that legume seed is overwhelmingly bought (50% of transactions) - rather than saved, gifted, or obtained through a seed distribution - with 89% of purchases unfolding in the informal sector, mostly from local markets. Unlike with maize, farmers’ use of agro-dealers to obtain legume seed is minimal. The article identifies six legume customer seed market segments, but only the two smallest are served by current strategy. Refinements to formal sector delivery can help extend reach (e.g. with small packs), but real advances demand strong informal sector innovations, such as expanding sale and seller categories to embrace traders and local markets. A recent multi-country review of seed legislation suggests there may be room for such expansion.
... This demonstrates that the flasks employed by the CSRs are indeed hermetic. The airtightness of the flasks is important not only to maintain the moisture content of the dried seeds but also to reduce the oxygen available for insects and fungi and for oxidation of seed components associated with ageing (Baoua et al. 2014;Groot et al. 2014;Williams et al. 2017a, b). ...
Article
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Seed conservation in rural communities of low-and middle-income countries located in tropical areas is particularly problematic, due to high relative humidity that promotes insect and fungal infestations and leads to rapid losses in seed viability. Seed conservation in those areas is affected by unreliable power supplies that do not allow the use of dehumidifying and refrigeration systems recommended for the long-term storage of seeds. We tested the dry chain, i.e., initial seed drying with a reusable desiccant in the form of zeolite beads followed by seed conservation in hermetic containers, in rural communities of Guatemala (Huehuetenango Department). In this region, a network of community seed reserves (CSRs) has been established to provide a safety backup for seed and to conserve local agrobiodiversity. Using a local maize variety in three communities, we compared the dry chain with the seed conservation methodology employed in the CSRs (i.e., undried seeds in hermetic flasks) as well as with seed conservation in open storage, both in the local CSR and in a farmer's granary. Seed conserved using the dry chain treatment maintained very high seed viability (> 80%) throughout the whole experiment (6 months) and reduced fungal and insect infestations (< 3%). In the other treatments, the viability declined significantly to an average of 52% non-viable and 19% infested seeds after 6 months of storage. The dry chain was demonstrated to be an excellent solution for enhancing seed conservation in biodiversity hotspots of tropical areas as well as for improving seed security for farmers.
... Some of the productivity enhancement appendages include access to mechanization, credit, extension service, markets and fair pricing, private sector participation, appropriate post-harvest technologies and functional policies. For instance, lack of capacity to store excess farm outputs may increase post-harvest losses and reduce profitability, which may make investment in agriculture less remunerative [2,23,24] . A similar study to estimate the magnitude, relative returns, and economic viability of five selected agricultural interventions in Ghana is worth sharing [20]. ...
Article
Post-harvest losses (PHL) have been identified as a crucial challenge to achieving food and nutrition security in sub-Saharan Africa. Access to reliable data and standardized methods of estimating PHL are a twin barrier to developing long term mitigation options and policies to reduce PHL. This study assessed PHL in 6 districts of the Upper East Region of Ghana to facilitate planning and dissemination of mitigating strategies. The second part involved participatory evaluation of improved storage technologies to reduce PHL in two vulnerable crops (maize and cowpea). Overall, farmers’ declared PHL were higher across the crops compared to laboratory measurement. Crops recording higher PHL were in order of cowpea (17.3%), Bambara nut (11.5%), groundnut (8.9%) and maize (8.2%). By disseminating appropriate technologies to farmers, PHL were reduced to 3.1% from 36.7% in maize and 6.4% from 77.8% in cowpea during 12 months of storage. In spite of the high PHL, the respondents showed low technical and resource capabilities to minimize losses. Other factors contributing to PHL were the small-scale nature of production, and high cost of improved techniques tailored for same smallholders. Although the improved storage methods were associated with high variable costs, all the treatments showed positive stream of discounted net benefits.
... Maize is a basic staple food grain for large parts of world including Africa, Latin America, and Asia [4]. It is an important cereal grain grown widely in sub-Saharan Africa as a staple food crop [5] contributes to food security of small-scale farmers [6]. In Ethiopia, maize is the second most widely cultivated crop and grown under diverse agro-ecologies and socioeconomic conditions typically under rain-fed [7]. ...
Article
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Maize is the primary staple crop grown, nearly in all agro-ecological zones of Ethiopia. Despite the steady production of maize, post-harvest losses of maize remained a serious challenge. In Ethiopia, traditionally farmers use different storages structure for their grain. Gombisa is one of above ground storage structure used by most of farmers. However, those traditional storage structures were not effective in protecting the grain from insect, microbial infestation and environmental factors. Farmers have indigenous knowledge of storage management practices to cop up with this post-harvest loss. The traditional wisdom and methods of storage can protect commodities from insect infestation for substantially longer periods. Among the farmers' practices; sun drying, use of botanicals, hanging over fire, mixing with wood ash, mixing with partially ground chillies (hot pepper), and storing unshelled maize were some of the storage practice proven effective in minimizing storage infestation. Some of these practices were also effective in controlling mould development that leads to the occurrence of aflatoxin. This review suggested that, modifying traditional storage structure and providing improved storage systems that are affordable for smallholder farmers, could be a possible option to mitigate post-harvest loss.
... The present findings are consistent with numerous previous studies reporting that hermetic containers can maintain grain quality of several commodities for over six months (Sanon et al., 2011;Hell et al., 2014;Baoua et al., 2016;Abass et al., 2018). Weight losses during storage are mainly caused by insect feeding on the grain and causing damage, but can also result on the fungal attack and grain metabolic activities such as respiration, although losses due to respiration are negligible in grain (Adhikarinayake et al., 2006;Baoua et al., 2014). The regression analysis showed that 72% of weight loss variation is explained by the insect density. ...
Article
Naturally infested paddy rice was used to compare the effectiveness of polypropylene bags and hermetic storage containers over 12 months of storage in a warehouse. Insect pest identification as well as the infestation level, percentage of damaged grain, weight loss, and moisture content were evaluated. Five insect species associated with stored rice were identified during the storage period, namely lesser grain borer (Rhyzopertha dominica), red flour beetle (Tribolium castaneum), rice/maize weevil (Sitophilus spp.), angoumois grain moth (Sitotroga cerealella) and flat grain beetle (Cryptolestes ferrugineus). The lesser grain borer was the most predominant species with an average incidence above 70% after twelve months of storage, followed by the rice/maize weevil with an incidence of 17%. When compared to hermetic storage containers, polypropylene bag showed the highest mean infestation level with 233.3 individuals/ kg after six months of storage, representing about 8-fold of the number of insects recorded in hermetic containers after six months of storage. In polypropylene container, the percentage of damaged grain and weight loss increased significantly achieving a maximum of 6.98% and 5.56% respectively, whereas using hermetic containers the highest percentage of damaged grain reached was 3.24% in polyethylene drum and the weight loss was 1.62% in GrainSafe bag. The results from the study show that the use of hermetic storage containers is a green alternative for safe storage of paddy rice, for 12 months without application of pesticides, bringing multiple advantages for smallholder farmers, lever food security and income generation for smallholder farmers and rice milling companies.
... Using plastic bags, such as PICS or polypropylene ones, to store dried kernels and protect them from mold infection and insect and rodent infestation also proved successful in a number of cases for reduction of mold growth and aflatoxin contamination during maize and groundnut storage (Baoua, Amadou, Ousmane, Baributsa, & Murdock, 2014;Magembe et al., 2016a;Maina, Wagacha, Mwaura, Muthomi, & Woloshuk, 2016;Ng'ang'a, Mutungi, Imathiu, & Affognon, 2016;Mutegi, Wagacha, Christie, Kimani, & Karanja, 2013). However, in groundnuts, higher levels of aflatoxins were seen in plastic bags (compared to jute bags), which were attributed to heat development in the bags. ...
Article
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Contamination of African staple foods is a major issue for human and animal health, nutrition, and trade. This review aimed to collect and synthesize the available evidence on geographical spread, scale of contamination, disease burden, economic impact, and mitigation measures for aflatoxins in Africa by way of a systematic literature review. This knowledge can enhance management strategies for the major challenges to combat aflatoxins. The search was conducted by applying a predefined search strategy, using bibliographic databases and websites, covering the period 2010 to 2018. Results showed that maize, peanuts, and animal feeds were the most studied commodities. For maize, all studies indicated mean AFB1 to exceed the European Union legal limit. From studies on contamination levels and biomarkers, it is clear that overall exposure is high, leading to a substantial increase in long‐term disease burden. In addition, concentrations in food occasionally can reach very high levels, causing acute aflatoxicoses. The trade‐related impact of aflatoxin contamination was mainly evaluated from the standpoint of aflatoxin regulation affecting products imported from Africa. There was a limited number of studies on health‐related economic impacts, pointing out a gap in peer‐reviewed literature. A number of mitigation measures have been developed, but proof of cost‐effectiveness or even costs alone of the practices is often lacking. We recommend more emphasis to be put in peer‐reviewed studies on evidence‐based cost‐effective mitigation strategies for aflatoxins, on the scale and spread of the problem and its impacts on public health and economics for use in evidence‐based policies.
... The punctures have been visually observed in our experiment on the surface of PICS inner bags. Most of the punctures were more frequent after nine to ten months of turmeric storage due to increased infestation and multiplication of insect populations, similar findings reported by Baoua et al. (2014). ...
Article
Hermetical and traditional storage bags were evaluated for their effect on the postharvest storage of turmeric at laboratory conditions. The traditional Polypropylene (PP) woven bags and the jute bags were compared with Purdue Improved Crop Storage (PICS), Super Grainpro, Savegrain bags, and Ecotect bags. Every month, for eleven months, the levels of oxygen and carbon dioxide, moisture, insect damage, live insect count, weight loss of turmeric rhizomes were monitored. A slight change in moisture was observed for turmeric stored in PICS, Grainpro, Savegrain, and Ecotect bags. But, a significant decrease in moisture was observed for turmeric stored in jute bags. The levels of oxygen in PICS and Ecotect bags decreased from 20% to 8% while carbon dioxide content increased in PICS bags from 0.2% to 12% during the period of storage. In jute bags, the level of oxygen was approximately 19.3% but the level of carbon dioxide increased from 0.05% to 0.43% due to insect activity. In all hermetic bags, the risk of insects has decreased over time, and weight loss has also decreased as compared with jute bags. In Polypropylene woven and jute bags, damage by insects and weight loss increased during storage while the curcumin content reduced. Our study showed the effectiveness of PICS, Grainpro, Savegrain, and Ecotec bags in controlling insects and weightloss in turmeric rhizomes over the traditional bags. All the four hermetic bags performed well in long-term storage of turmeric rhizome and can be recommended.
... Insect-induced perforations were also recorded on the liners of PICS bags used to store maize grain for 6.5 months in West Africa (Baoua et al., 2014). However, laboratory studies by García-Lara et al. (2013) on the SGB concluded that it could not be perforated from the inside by insect pests resident in the grain, although they found it could be perforated by insects arriving from the outside of the bags. ...
Article
Smallholder farmers in sub-Saharan Africa store harvested maize to provide food stocks between harvest seasons, which may be up to 12 months apart. Stored maize is highly susceptible to insect pest damage, hence the need for stored grain protection technologies such as hermetic bags. The current study evaluated the efficacy of five brands of hermetic bags in storing three maize varieties under two contrasting agro-ecologies in Guruve and Mbire districts of Zimbabwe, for two storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bag (SGB) IVR™, PICS bag, AgroZ® Ordinary bag, AgroZ® Plus bag and ZeroFly® hermetic bag, which were compared to grain stored in a polypropylene bag either untreated (negative control) or following admixture with a synthetic pesticide treatment, Actellic Gold Dust® (positive control). The maize varieties included a white hybrid, a pro-vitamin A biofortified orange and a local variety. All the hermetic bag treatments out-performed the synthetic pesticide in limiting grain damage and weight loss during storage. No significant difference in grain damage or weight loss was observed among the hermetic bags. However, rodents punctured some hermetic bags; therefore rodent control is recommended. A positive correlation with grain damage and weight loss for all three maize varieties was found for Sitophilus zeamais, Sitotroga cerealella, Tribolium castaneum and Cryptolestes spp adult numbers. Significantly higher insect damage and weight loss (P < 0.001) occurred in the white hybrid maize than in the other two varieties. The results confirmed that regardless of brand, all the hermetic bags tested can be recommended for smallholder farmer use to limit postharvest storage losses, avoid pesticide use, and support food and nutrition security.
... PICS bags are trademarked hermetic bags that have two inner bags made of high-density polypropylene with an outer woven polypropylene bag. These bags were developed to reduce insect damage but have been successfully used to reduce the risk of aflatoxin contamination in maize [33,34]. Within the context of water management and reducing contamination from pathogens at the community and household levels, the following approaches have been suggested: using different containers for transporting and storing water from different sources (especially potable vs. non-potable), digging separate traditional wells for animal and human use (ongoing work in Chad), control access to potable water sources by enclosing the source with available natural material, and importantly expanding key messages around hygiene to emphasize reducing exposure to animal feces as well as human feces [22,35]. ...
Article
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Objective To implement and measure the effects of a multi-level multi-sectoral social behavior change (SBC) intervention in Agago District of Northern Uganda and to determine the potential for scale-up. Intervention Compare the Nutrition Impact and Positive Practice (NIPP) approach to a NIPP+ approach. The NIPP approach involves nutrition education and SBC, whereas the NIPP+ adds agricultural inputs, training, and tools to support improved farm and water quality practices. The intervention effect will be measured through lower levels of aflatoxin in grain, lower water contamination, and improved knowledge on nutrition and health. Design This is a three-arm cluster-randomized controlled superiority trial (cRCT). The study arms include the following: group 1: NIPP; group 2: NIPP+, and group 3: control. Groups 1 and 2 will receive a 12-week intervention (NIPP or NIPP+) with active monitoring and longitudinal follow-up at 2, 6, and 12 months post-intervention. Additionally, an in-depth process and performance evaluation of each intervention arm will be undertaken using quantitative and qualitative methods. A total of 60 clusters from 5 subcounties of the Agago district will be randomly selected, and 15 households per cluster will be recruited using specific inclusion/exclusion criteria for a total of 900 households (300/arm). Respondents for the qualitative portion will be purposely selected. Analysis We will collect data from all participants at 3 time points: baseline, endline, and 12 months post-intervention. The analysis will utilize intent-to-treat (ITT) using the initial randomization of the treatment arms to determine the overall impact of having the NIPP vs. NIPP+ vs. control. Mixed effects models will be used to determine the role of time-variant and invariant individual household, and community characteristics, as well as measures of exposure and integration on key outcome indicators. A difference-in-difference analysis (baseline/endline, baseline/12 months post-intervention, endline/12 months post-intervention) will also be used to triangulate findings. Trial registration NCT04209569 . One Nutrition in Complex Environments (ONCE) Registered 24 December 2019
... The second aspect of the demonstration focused on storage where the research team showcased the superiority of hermetic triple-layered bags. These bags have been proven to be effective for the storage of grains (Baoua et al. 2014). The soybeans harvested from the demonstration plots were stored in the hermetic bags after drying while the produce from the farmers' field were stored, as usual, in single-layered jute sacks. ...
Article
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This study relies on a triple-hurdle model to estimate the factors that determine farmers’ decision to participate in a peer dissemination project and then share the knowledge gained with other farmers. The first hurdle estimates show that proximity, income and social contacts determine participation. The second hurdle estimates further show that access to information, being a male and farming experience have positive effects on facilitating a higher level of participation. Estimates of the final hurdle suggest that geographical location plays a role in determining the number of farmers that participants of a peer dissemination project can contact.
... Black rice is mainly produced in South-East Asian year in India, may fulfil the food requirement of its one-third poor population ( Nagpal & Kumar, 2012 ). Besides, pest infestation also leads to quality deterioration thus significantly affecting the commercial value including the marketability of the cereal and as projected earlier through an economic model, ∼1% of pest infestation in maize subsequently results in value depreciation of maize by 0.6% -1% ( Compton et al., 1997 ;Baoua et al., 2014 ). ...
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Rice (Oryza sativa L.) is one of the most important cereal crops that serve as staple food of more than 50% of the world population. In recent years great interest has been shown in pigmented & colored rice due to its culinary interest as well as associated health benefits. However, post harvest qualitative and quantitative losses in rice during storage through pests are significant; therefore strategies that are aimed at minimizing losses in the supply chain can have significant socio-economic impact as it may strengthen ‘Food Security’. Fumigation is quite often employed but it is being gradually phased out owing to health and environmental concerns. In the current investigation, effect of different doses of gamma radiation (0.25-1.0 kGy) on the quality attributes (gel consistency, water uptake, total anthocyanin content, phenolics, protein and antioxidant activity) of different prominent ethnic pigmented rice cultivars (5 types) from the state of Manipur, India was evaluated. The cultivars displayed significant variation in their physical quality attributes including dehusked grain color, grain weight and length/breadth ratio. No significant difference was observed in the gel consistency profile of these rice cultivars upon gamma radiation processing (0.25-1.0 kGy). A wide variation was observed in the total anthocyanin content (0.17-4.90 mgCy-3-glu/g in non-irradiated samples) for these pigmented rice cultivars and radiation processing was also observed to exert differential impact on the anthocyanin content (0.24-3.96 mgCy-3-glu/g in irradiated samples) in different cultivars. Total phenolics content (0.22-2.46 mgGAE/g in non-irradiated samples) marginally increased (0.32-2.47 mgGAE/g in irradiated samples) in all the rice cultivars upon radiation processing. Rice cultivars also displayed prominent antioxidant capacity (DPPH scavenging: 20.5-80.5% in non-irradiated samples) and this functional health protective property was found to be retained (DPPH scavenging: 20.8-80.7% in non-irradiated samples) upon gamma irradiation.
... Similarly, Chigoverah et al. (2014) reported percentage of insect damage of grains stored in metal silos and HGBs (Hermetic grain bags) were smaller (10.11 and 7.40) in comparison with other storage structures. Baoua et al. (2014) also compared the storage efficiency of PICS bags against conventional storage structures and reported that damaged maize grain due to insect pests was 6 fold in conventional storage structures as compared to samples stored in PICS bags. Similarly, the report of Ngwenyama et al. (2020) in comparative performance of five hermetic bag brands during on-farm smallholder cowpea showed that, hermetic bag treatments were significantly superior to non-hermetic storage in limiting the product damage. ...
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Grain crops are the dominant source of nutrition for the majority of the world's population, particularly in developing nations. However, mainly in traditional storage methods, significant grain losses are incurred due to rodents, insect pests, and environmental conditions. To meet the food demand for the ever-increasing world population, it is necessary to address the issue of grain loss to pest damage in storage. In line with the potential of different hermetic storage technologies (PICS bags, Metal Silos and Polypropylene bags + low-density Poly-ethylene bags) and conventional Jute Sacks and Polypropylene bags in maintaining the quality of the grain over 7months of storage were evaluated. Compared with traditional jute sacks and Polypropylene bags, all hermetic storage methods showed better storage performance in retaining germination capacity, nutritional composition and reduced the percentage of seed damage. Of all storage methods, Metal silos and PICS bags were the most effective in reducing both quantitative and nutritional losses of the grain. They reduced the percentage of seed damage below 3.8%, but the percentage of grain damage in Jute sacks was as high as 61.2%. It is recommended that smallholder farmers can use either metal silo or PICS bags to store their grains.
... Maize is a substantial contribution in the diets of rural and urban populations. Its cultivation increased gradually over the years thanks to adoption of best production technologies and improved varieties [3]. This crop is generally cultivated by small-scale farmers and widely grows across various ecological zones, from the northern savannah till the rain forest belt in the south [4], with a yield of 1,025,000 tons in 2017/2018 from 523,538 ha of total cultivated area [2]. ...
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... Hermetically sealed storage bags, such as those of the Purdue Improved Crop Storage project, is apparently effective for insect control, increasing insect mortality by 95-100% in stored maize (Baoua et al., 2014;Hell et al., 2014). The Purdue Improved Crop Storage (PICS) bags are simple and provide a cost-effective way of storing grain and seed without using chemicals to control insect pests. ...
... These results demonstrate that cowpea will continue to remain the most important crop that drives the commercialization (demand) of hermetic bags in Niger. All other crops stored in PICS bags are known to be susceptible to insect pests and the technology has proven to be effective in their preservation [32][33][34]. Most secondary commodities (crops other than cowpea; i.e., Bambara nuts and hibiscus seeds) stored in PICS bags are primarily grown by women; and processed for home consumption and/or sold to generate income [25,35]. ...
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Cowpea is a food security crop and a main source of income for farmers in Niger. However, postharvest storage remains a major challenge due to insect pest attacks. Since 2008, the Purdue Improved Crop Storage (PICS) bags were disseminated in Niger to reduce storage losses. This study was conducted to assess the adoption of the PICS technology in the Dosso, Maradi, and Zinder regions of Niger. We interviewed 600 households selected from villages that did and did not benefit from PICS extension activities. A logit regression model was used to assess the decision of farmers to adopt the PICS technology. The overall adoption of the PICS bags among farmers was 48.4%. PICS adoption was 69.7% in Dosso, 41.3% in Zinder, and 31.2% in Maradi. Farmers who attended PICS training were 5 times more likely to adopt the technology than those who did not. Variables that affected the adoption of the PICS technology included the region, participation in PICS training, and information source. Beyond cowpea, PICS bags were used to store a variety of crops including Bambara nuts, hibiscus seeds, peanuts, millet, and sorghum. Storing 100 kg of cowpea in a PICS bag generated a cash flow of $70.38 per respondent and a net return of $21.50. Revenues generated from sales of cowpea stored in PICS bags were mostly used for health expenditures and to purchase agricultural inputs. Results of this study demonstrate that pest management technologies such as PICS bags can also contribute to improving the livelihood of family farms.
... This is a sealing technology that works by strictly limiting the inflow of oxygen into the bulk grain. PICS bags can reduce the growth of insect populations in storage by 98% and can reduce grain losses due to insects and molds in storage to less than 1% while maintaining their quality for months or longer [23][24][25]. In addition to this, there are plastic silos [24], grain safety bags [26], and Grain Pro Super bags [27], which are containers with a multilayer composite technology for better gas-tight storage. ...
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The scientific rationality of farmers' grain storage technology and equipment is crucial for the biosecurity of grain in the main grain-producing areas represented by Northeast China. In this paper, four farmer grain storage mock silos of different widths were used as a means to track an experimental cycle of grain storage. The absolute water potential of corn in all four silos at the beginning of the experiment was greater than the absolute water potential of air, prompting moisture migration from the grain interior to the air and down to about 14%. Moisture was influenced by wind direction, and moisture decreased faster with better ventilation on both sides of the grain silos. Therefore, grain silo width has a significant effect on the drying effect under naturally ventilated conditions of maize ears. This research focused on the determination and assessment of mycotoxin contamination under farmers' storage grain conditions and analyzed the effect of silo structure on the distribution of mycotoxin contamination. When the width was too large, areas of high mycotoxin infection existed in the middle of the grain silo, and ventilation and tipping could be used to reduce the risk of toxin production. This study proved that reasonable farmer grain storage techniques and devices in Northeast China can effectively protect grain from mycotoxin contamination.
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The present study aims to evaluate the effectiveness of high-density polyethylene container combined or not with Super Grain Bag for cowpea grain storage. The experiments were conducted on-station and on-farm. The storage systems tested included high-density polyethylene container (PC), Super Grain Bag (SGB), and polypropylene bag (PB). The insect infestation level and grain damage were determined monthly for 6 months at on-station and every 2 months for 8 months at on-farm trials. Acceptability test of the stored grain was carried out at the end of on-station trials with farmers. Naturally infested grain was used, with an initial infestation level of 117 insects/kg and a percentage of damaged grain of 27%. After 6 months of storage on-station, PB resulted in an increase of insect infestation to above 1300 insects/kg of cowpea grain and an increase of damaged grain to 79%. In the SGB and PC, the number of insects increased to 573 and 364 insects/kg, while the grain damage increased to 40% and 36%, respectively. After 4 months of storage the SGB was perforated by insects, compromising its hermeticity. The combination of PC with SGB (PC + SGB) reduced the proliferation of insects and grain damage, resulting in 257 insects/kg and 34%, respectively. The farmers highly accepted grain stored at PC and PC + SGB systems. The on-farm trials confirmed the effectiveness of the polyethylene container on limiting insects multiplication and grain damage. Thus, the polyethylene container, associated or not with Super Grain Bag, showed to be effective for storage and preservation of cowpea grain, making it suitable for smallholder farmers, thereby reducing cowpea grain losses during storage. K E Y W O R D S cowpea, polyethylene container, smallholder famers, Super Grain Bag
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Farmers continue losing substantial quantities of grain during storage due to damages from pests including insects. Hermetic bags, being promoted in Ethiopia, could be viable alternatives to traditional methods and insecticides that are commonly used by farmers to store grain. However, the economics and determinants behind farmers’ decisions to use different storage methods are poorly understood. This study sought to ascertain the economics of hermetic grain storage technology among 450 representative small-scale maize farmers in northwestern Ethiopia. Gross margin (GM), and the marginal rate of return (MRR) were employed to estimate the economic costs and benefits of storage methods, while a multivariate probit regression model was employed to analyze the determinants of farmers’ decision to store maize with a given storage method. The results show that farmers used a combination of different storage techniques: 19.6% did not store grain, 87.8% used traditional methods with pesticide, and 66.7% used Purdue Improved Crop Storage (PICS) hermetic bags. Farmers who used hermetic bags also used other mentioned storage techniques. PICS had the highest GM (US$21.77 100 kg–1) and MRR (3.196), indicating that they were the most profitable. Moreover, a household could obtain an additional net cash flow of US$5.02 100 kg-1 PICS bag per season after 9.6 months of storage. Farmers’ decisions to use PICS bags were influenced by several factors including access to information, the initial cost, and storage capacity of the technology. Thus, increasing awareness and improving supply chain efficiency to reduce the cost of the PICS bags would improve adoption rates.
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The performance of six grain storage technologies for the control of insect pests in maize was evaluated over a 36-week (9-month) storage period. The six technologies used were: two ZeroFly® hermetic bag brands (laminated and non-laminated); Purdue Improved Crop Storage (PICS) bag; non-hermetic ZeroFly® bag; woven polypropylene (PP) bag containing maize grain treated with Actellic Gold® Dust (pirimiphos-methyl 1.6% + thiamethoxam 0.3%) and woven PP bag containing untreated grain. Each bag was filled with 50 kg maize grain and four replicates of each were set up. With the exception of the non-hermetic ZeroFly® bag, 50 live adults of the larger grain borer Prostephanus truncatus and of the maize weevil Sitophilus zeamais , were introduced into all the bags. Insects were not introduced into the non-hermetic ZeroFly® bag to assess its effectiveness in repelling infestation from outside. Parameters recorded were gas composition (oxygen and carbon dioxide) levels inside the bags; weight of flour generated by insect feeding activities; grain moisture level; live adult insect counts; grain damage and weight loss; grain germination rate and aflatoxin level. At termination, the plastic liners of the hermetic bags were examined for perforations. Results show that oxygen depletion and carbon dioxide evolution were faster in ZeroFly® hermetic compared to PICS bags. Throughout the 36-week storage trial, grain damage remained below 4% and weight loss below 3% in all the treatments except in the untreated PP bags in which it increased to 81.1 and 25.5%, respectively. The hermetic PICS, ZeroFly® and Actellic Gold dust-treated PP bags maintained grain germination at 60%, which was lower than the initial 90%, while in untreated control, it reduced to 4.7%. The mean aflatoxin levels fluctuated between 0.39 and 3.56 parts per billion (ppb) during 24 weeks of storage in all the technologies tested, which is below the acceptable maximum level of 10 ppb in maize. Based on the evaluation results, it can be concluded that hermetic PICS and ZeroFly® bags and woven PP bag with Actellic Gold dust-treated grain effectively protected stored maize grain from insect attack and weight losses. Appropriate strategies and mechanisms for the effective and efficient adoption of hermetic storage bag technology at scale would contribute towards global food security.
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Aflatoxin contamination of maize remains a serious challenge in developing countries in the tropics where it is pervasive due to favourable environmental conditions and high consumption of maize. An assessment of the triple-layer hermetic bag and a conventional bag (polypropylene bag) effectiveness to control the aflatoxin content in insect-free and insect-infested stored maize was studied over a six month period at the farm level. Moisture content, temperature, relative humidity, oxygen depletion, carbondioxide elevation and grain damage were analysed during storage. Seasonal changes resulted in significant fluctuation in grain moisture content, temperature and relative humidity in different storage bag technologies and storage environment. Analysis of variance also showed significantly differences (p<0.05) in the degree of insect damage and the corresponding levels of aflatoxins in hermetic and polypropylene bags. The initial mean percentage damage and aflatoxin content of 1.24% and 38.2 μg/kg respectively, in either storage bag technology increased significantly following seasonal changes and insect metabolic activities. Prostephanus truncatus-infested maize in the polypropylene bags recorded the highest damage (97.9%) with a corresponding aflatoxin level of 227.7 μg/kg after six (6) months storage. An aflatoxins level (>70 μg/kg) was recorded in the triple-layer hermetic bags despite the bags excellent prevention of insect activities (<5%) over the same period of storage. Triple-layer hermetic bags have limited capacity to abate further accumulation of aflatoxins in previously aflatoxin-contaminated grains in the tropics.
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In this paper, we try to understand what the main causes of food losses (FLs) are. Our results show that producers' education and experience and the number of years in which a producer has been involved in the production of a specific crop are significantly correlated with reduction in FL. Unfavorable climatic conditions, pests, and diseases, as well as limited knowledge and access to equipment, credit, and markets, are also challenges to increasing production of higher quality and therefore reasons for FL. Policies to reduce and prevent FL need to be targeted to specific commodities and contexts. JEL CLASSIFICATION Q13; Q18; Q58
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Cereals, legumes and nuts are widely produced and consumed in Nigeria. Despite the availability of these food crops, their safety is often compromised by the presence of mycotoxins. In Nigeria, mixtures of several mycotoxins, including the highly carcinogenic aflatoxins together with fumonisins, ochratoxins and the trichothecenes, commonly co-occur in cereals and nuts than in legumes, thus, posing serious health risks to consumers. Physical interventions such as hand-sorting, cleaning/washing and other simple control measures (e.g., winnowing) could be effective to reduce mycotoxin exposures especially in resource-scarce rural areas. However, food crops are frequently stored prior to or after applying these measures. Hence, if storage conditions are inappropriate, other intervention strategies may fail due to increased accumulation of mycotoxins under poor storage. Moreover, poor storage practices may encourage infestation by insects and pests that can cause grain damage leading to contamination by toxigenic fungi. In addition, the market value of such grains will be adversely affected and this can contribute to economic loss and poverty at household level. This review provides data on mycotoxin contamination of grains in Nigeria, mycotoxins in biological fluids, and showcases various poor grain storage practices. Furthermore, viable alternatives for improved grain storage, which can be applied in Nigeria, was suggested as a means to reduce mycotoxin exposure and to safeguard consumer health.
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This article aimed to study the effect of the infestation of Sitophilus species on the average weights of wheat, maize, and rice grains stored under laboratory conditions for one year. The average weights of grains were gradually decreased along year months from 10 kg reaching 7 kg at the end of the experiment. The wheat weevil, Sitophilus granarius insects appeared in the wheat grains at the second month of storage with a few numbers (1 insect / kg grains) and gradually increased along year months recording 80 insect / kg grains at the end of the experiment. The average weights of maize grains were gradually decreased along year months from 10 kg reaching 6 kg at the end of the experiment. Results also indicated that there were no damage or infestation at the first month of storing, meanwhile the damage start to increase at the third month recording 5 % , and 7 % after 4 months , and continued in increase recording 65 % after 12 months of storing. The maize weevil, Sitophilus zeamais insects appeared in the maize grains at the second month of storing with a few numbers (2 insect / kg grains) and gradually increased along year months reaching 75 insect / kg grains at the end of the experiment. The average weights of rice grains were gradually decreased along year months from 10 kg reaching 6 kg at the end of the experiment. The rice weevil, Sitophilus oryzae insects appeared in the rice grains at the second month of storing with a few numbers (2 insects / kg grains) and gradually increased along year months recording 75 insects / kg grains at the end of the experiment.
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This study was conducted in order to evaluate leaf powder botanical products of Eucalyptus (Eucalyptus macrorhyncha F. Muell), pawpaw (Carica papaya L.), neem (Azadirachta indica A. Juss) and lantana (Lantana camara L.) against the infestation of maize weevil, Sitophilus zeamays (L.) on stored maize grains. These botanicals were compared with synthetic chemical (Actellic Super Dust) and without insecticides application as controls. All tested plant products performed well in the reduction of live insects during maize storage as compared to the no insecticide application. However, pawpaw leaf powder was the most effective in reducing the number of live insects. Similarly, number of damaged maize seeds was relatively less in grains treated with pawpaw leaf powder. This also reflects on the weight loss where the maize grains treated with pawpaw leaf powder were lowest. The weight loss was also less in grains treated with neem and eucalyptus leaf powders. This study suggests that pawpaw, neem and eucalyptus leaf powders can be used as good alternatives to synthetic pesticides against S. zeamays.
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Maize was artificially infested with either 10 or 25 individual Prostephanus truncatus (Horn) and Sitophilus zeamais (Motschulsky) or a mixture of both, and stored in a hermetic grain bag (HGB) or a woven polypropylene bag (WPB) for 150 days. Population growth of P. truncatus and S. zeamais during storage was low in HGB, while in WPB, the insect population increased significantly with storage duration. Mortality rate during storage was significantly higher in HGB than in WPB. After 60 days of storage, the average mortality rate of 99.50% was observed in HGB infested with 25 P. truncatus, and 100% for S. zeamais at the same infestation density after 90 days of storage. Grain losses were significantly lower in HGB compared with WPB. Less than 0.5 and 6.0% losses were obtained, respectively, for S. zeamais and P. truncatus in HGB infested with 25 individual insects after 150 days of storage, whereas losses of 19.2% (infestation with S. zeamais) and 27.1% (infestation with P. truncatus) were observed in WPB. HGB seems to be resistant to the perforation of S. zeamais, but not to P. truncatus. The moisture content of maize grains stored in HGB remained practically the same during storage, compared with the levels in WPB, which reduced with storage time. HGB could be used for maize storage, protecting it against insect infestation without the need for insecticide use.
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Oxygen (02) depletion and carbon dioxide (C02) enrichment of the intergranular atmosphere fonn the basis for suppressing and controlling insect infestations during hennetic storage of dry grain. Traditional methods and recent improvements are reviewed, and modem structures designed for hennetic storage at the com-mercial and fanner levels are described. Improvements needed to render the hennetic concept more widely acceptable are enumer-ated, and the development of hennetic storage within flexible plastic liners is evaluated on the basis of more than a decade of experience in hot climates. A preliminary model is employed to simulate the interdependent changes in gas concentrations, insect populations and amounts of grain consumed. A theoretical ingress rate of 0.05% 02/day was found sufficient \0 arrest development of residual insect infestations. Potential niches for hermetic storage applications in developing and technologically advanced countries are identified. In tropical climates aeration for cooling of grain is not feasible, reinfestation is frequent and the available contact insecticides degrade rapidly because of high temperatures. The advantages of long-tenn hermetic stomge in technologically advanced countries, and as a medium-term, user-friendly technol-ogy in developing countries, are stressed. In sharp contrast to the use of chemicals, hermetic storage is environmentally sound and poses no risk to storage operators, consumers or non-target organisms.
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Traditional storage practices in developing countries cannot guarantee protection against major storage pests of staple food crops like maize, leading to 20-30% grain losses, particularly due to post-harvest insect pests and grain pathogens. As a result, smallholder farmers end up selling their grain soon after harvest, only to buy it back at an expensive price just a few months after harvest, falling in a poverty trap. The potential impact on poverty reduction and greater livelihood security will not be realized, however, if farmers are unable to store grains and sell surplus production at attractive prices. Apart from causing quantitative losses, pests in stored grain are also linked to aflatoxin contamination and poisoning. To address this problem, a metal silo was developed as a valid option and proven effective in protecting stored grains from attack by storage insect pests. A metal silo is a cylindrical structure, constructed from a galvanized iron sheet and hermetically sealed, killing any insect pests that may be present. The impact of metal silo technology in Africa. Asia and Latin America includes, improving food security, empowering smallholder farmers, enhancing income opportunities and job creation, and safeguarding the agro-ecosystems. The metal silo can be fabricated in different sizes, 100 kg-3000 kg holding capacity by trained local artisans, with the corresponding prices of $35 to $375. The use of metal silo, therefore, should be encouraged in order to prevent storage losses and enhance food security in developing countries. (c) 2010 Elsevier Ltd. All rights reserved.
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An experiment was conducted to determine the importance of husk covering on field infestation of maize by the maize weevil, Sitophilus zeamais, at Bako, western Ethiopia. Five maize genotypes, G1 (SZSYNA99-F 2 -33-4-2 X SC 22), G2 (CML-197 X SZSYNA99-F 2 -33-4-1), G3 (SZSYNA99-F 2 -79-4-3 X CML-197), G4 (BH-140) and G5 (Bukuri) were used. There were differences among the maize genotypes in their resistance to the maize weevil. The genotypes, G2, G3 and G5 had good husk characteristics (extended tip and tight husk) and flint grains resulted in low number of weevils and damaged ears. On the contrary, the genotype G1, with dent-flint-grain, poor husk characteristics (bare tipped and loose husk cover), harbored the highest number of weevils and suffered ear damage followed by the genotype, G4. Therefore, husk tip extension and husk tightness were the two most important characters conferring resistance to maize ears against the maize weevil in the field.
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Restrictions due to the adverse effects of pesticide residues in food and the environment resulted in the imposition of strict limitations on pesticide registration by regulatory agencies. Consumer demand for chemical-free and insect contamination-free products increased the attention to the application of non-residue organic technologies for the protection of stored grain. Among the new gaseous application technologies that have successfully replaced fumigants are the manipulation of modified atmospheres (MAs) through the use of biogenerated MAs, for insect control and for quality preservation of seeds, stored paddy, polished rice, wheat, pulses, cocoa or coffee beans, and high moisture corn. This takes advantage of the atmospheric gas composition produced by the respiratory metabolism of the biological agents of the grain bulk to prevent insect development and suppress microflora activity. Sufficiently sealed structures enable insects and other aerobic organisms in the commodity, and/or the commodity itself, to generate the MA by reducing the O 2 and increasing the CO 2 concentrations. Further moisture levels stay constant preventing mold growth.
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Maize remains crucial for food security in Sub-Saharan Africa. In some regions, the predominance of the crop in farming systems and diets implies that yield gains have the potential to jump-start a Green Revolution like those experienced in Asia for rice and wheat. However, despite episodes of success, the evidence compiled here suggests that very little progress has been made toward achieving this potential in recent years. Reversing this condition remains crucial to agricultural growth and food security in Africa. Over the long term, large investments and sustained political commitment are needed to ensure strong plant breeding and seed systems to serve smallholders, predicated on improved crop management practices to protect soils and cope with unreliable rainfall, and access to appropriate labor-saving technologies. More innovative extension and advisory systems are also needed to facilitate farmer learning and adapt techniques and technologies to local environmental and social conditions. Better financial services, perhaps including new forms of insurance, are needed for smallholders.
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In April 2004, one of the largest aflatoxicosis outbreaks occurred in rural Kenya, resulting in 317 cases and 125 deaths. Aflatoxin-contaminated homegrown maize was the source of the outbreak, but the extent of regional contamination and status of maize in commercial markets (market maize) were unknown. We conducted a cross-sectional survey to assess the extent of market maize contamination and evaluate the relationship between market maize aflatoxin and the aflatoxicosis outbreak. We surveyed 65 markets and 243 maize vendors and collected 350 maize products in the most affected districts. Fifty-five percent of maize products had aflatoxin levels greater than the Kenyan regulatory limit of 20 ppb, 35% had levels > 100 ppb, and 7% had levels > 1,000 ppb. Makueni, the district with the most aflatoxicosis case-patients, had significantly higher market maize aflatoxin than did Thika, the study district with fewest case-patients (geometric mean aflatoxin = 52.91 ppb vs. 7.52 ppb, p = 0.0004). Maize obtained from local farms in the affected area was significantly more likely to have aflatoxin levels > 20 ppb compared with maize bought from other regions of Kenya or other countries (odds ratio = 2.71; 95% confidence interval, 1.12-6.59). Contaminated homegrown maize bought from local farms in the affected area entered the distribution system, resulting in widespread aflatoxin contamination of market maize. Contaminated market maize, purchased by farmers after their homegrown supplies are exhausted, may represent a source of continued exposure to aflatoxin. Efforts to successfully interrupt exposure to aflatoxin during an outbreak must consider the potential role of the market system in sustaining exposure.
Article
Insect species and damage levels were evaluated and related to aflatoxin content in maize sampled from farmers' stores in four agroecological zones over a two-year period in Benin, West-Africa. In 1993, no aflatoxin was detected in maize that was free of insect damage. In the same year, in maize with more than 70 % of cobs damaged by insects 30.3 % were aflatoxin-positive, with a mean aflatoxin contamination of 77.8 ppb (parts per billion or μg/kg). Grain moisture increased with damage levels. The mean aflatoxin content of maize infested with Carpophilus dimidiatus Fabricius (Coleoptera: Nitidulidae) was significantly higher than maize free of this pest (F = 5.05, P ≤ 0.05). In 1994/95, the density of Mussidia nigrivinella Ragonot (Lepidoptera: Pyralidae), was significantly higher in the Northern Guinea Savanna than in the other zones, and the presence of this pest was positively correlated with the cob area visibly infected with Aspergillus flavus Link (Deutoremycetes: Monoliales) (r = 0.239, P ≤ 0.05) early in storage. Six months later, damage levels due to insects were significantly lower in the Sudan Savanna than in the other ecozones. The infestation level of the most common storage pest, Sitophilus zeamais Motschulsky (Coleoptera: Curcilionidae) decreased from the south to the north. After six months of storage aflatoxin level was positively correlated with the cob area damaged by Sesamia calamistis Hampson (Lepidoptera: Noctuidae) (r = 0.25, P ≤ 0.05), the number of Cryptophlebia leucotreta (Meyrick) (Lepidoptera: Tortricidae) observed on maize (r = 0.26, P ≤ 0.05) and cob area damaged by S. zeamais (r = 0.22, P ≤ 0.05).
Article
Cowpea is the most economically and nutritionally important indigenous African grain legume, grown by millions of resource-poor farmers. It is a key cash crop in areas too dry to grow cotton or other export crops. Most of the over 3 million t of cowpea grain produced annually in West and Central Africa is grown on small farms. Storage is often identified as the key challenge for small scale cowpea growers. Many farmers sell cowpea grain at low harvest time prices rather than risk losses by bruchids during storage. Some traditional methods are effective for small quantities (e.g., 10 kg), but are difficult to scale up. Some effective storage chemicals are available, but they are regularly misused by farmers and merchants. The Purdue Improved Cowpea Storage (PICS) Project is addressing these problems through promotion of hermetic storage in triple layer sacks which have an outer layer of woven polypropylene and two liners of 80 μ high-density polyethylene. Village demonstrations with more than 45, 000 PICS sacks have shown the technology to be effective. Good quality affordable sacks have been produced by manufacturers in Nigeria, Burkina Faso and Mali. Over the past three years more than one million sacks have been produced and sold. Despite the success with the outreach activities and the farmer adoption, the challenge remains to develop sustainable sack distribution networks. Issues identified include reluctance of wholesalers to order sacks due to risk associated with a new product, inability of wholesalers to develop effective distribution networks due to difficulties with enforcing contracts, and limited access to capital. The PICS project is exploring new ways to address some of these issues, including using non-traditional distribution systems for PICS sacks such as agro-dealers networks, and adapting distribution systems that have worked for cell phones and other products.
Article
There are many challenges facing small scale farmers especially in Africa and other developing countries that lead to grains post-harvest losses. Amongst these are inadequate storage facilities, rodents, insects and birds. It was predicted that the world's population will increase to about 9.1 billion people by the year 2050 and most of this increase will occur in developing countries. Hence, the need of investing much to the agricultural sector is necessary in order to produce more food to feed the world. Furthermore, increasing agricultural productivity must go hand-in-hand with improved storage in order to reduce post-harvest losses. Promoting small scale agriculture is the key to achieving food security in developing countries. In this work, metal silo technology for small and medium scale farming was developed for more comfortable and effective grains protection. Air-tightness of the silo was achieved by adding rubber stopper under grains-inlet and discharge lids. Locking points on grains inlet and discharge covers with padlock was designed. Larger size of this silo was modernized to be mobile facilitated with wheels-metal-frame stand for easy repositioning, which replaced the ordinary method of concrete stands and pallets. Cheaper methods of grains moisture control, cleaning and safe emptying of the silo were also provided. Metal silo can be fabricated as cylindrical, square or rectangular prism in shape, also in different sizes of 50 to 3,000 kg holding capacity of grain such as rice, maize, wheat, guinea-corn, millet and beans.
Article
Hermetic or airtight storage of grain to suppress development of destructive populations of storage insect pests is an ancient technology that is finding modern applications in developing nations. Unprotected cowpea grain can be destroyed by unchecked growth of the bruchid, Callosobruchus maculatus (Walp). If the grain is kept in triple-layer hermetic plastic bags, losses are averted. The history, development and mode of action of triple-layer bagging for cowpea storage is reviewed here, as are lessons learned while bringing the technology to low-resource farmers in the developing nations of West and Central Africa. The success of the technology owes in part to the engagement of low resource farmers at virtually all stages of development, testing and extension of the technology.
Article
Aflatoxin B1 is a potent hepatacarcinogen that occurs in corn worldwide. The aflatoxin‐producing fungus Aspergillus flavus can grow and produce aflatoxin on corn preharvest and in storage. Within the U.S., aflatoxin contamination of preharvest corn has been reported in 23 states, and contamination is chronic in the southeastern U.S. where hot, drought conditions often favor the fungus and the production of aflatoxin. Management practices have been developed to reduce aflatoxin contamination, but in years when environmental conditions are extremely favorable for the fungus, no control strategy is effective. Resistance to aflatoxin accumulation appears to be heritable, but no commercial hybrids are available with adequate resistance. This review covers the epidemiology of A. flavus in preharvest corn from the infection process to the factors that influence aflatoxin formation. Also discussed are the problems associated with the development of resistant varieties and new strategies that are being developed for control of aflatoxin contamination.
Article
Grain of maize, infested as well as uninfested with Prostephanus truncatus Horn, was stored for 15 days at 27°C under hermetic and non-hermetic conditions. Grain moisture content (m.c.) was adjusted to 14, 15, 16 and 17%. Under hermetic conditions at 3 days storage, oxygen levels were 0.8, 0. 6, 0.4 and 0.0% in grain with 14, 15, 16 and 17% m.c., respectively. However, at 6, 9, 12 and 15 days, the oxygen level dropped to 0% in all tested m.c. Insect mortality at 3 days storage under hermetic storage conditions ranged from 5 to 30%. At 6 days, insect mortality was 100% in maize with 14, 15 and 17% m.c. and 95% in grain with 16% m.c.; however, at 9 days of this m.c., mortality was 100%. In open storage, during the whole storage period and under all m.c. tested, P. truncatus manifested 0% mortality. The predominant fungus was Aspergillus ruber. The presence of this fungus was directly related to the m.c. and length of storage. Under hermetic conditions, in all m. c, the percentage of grain invaded by A. ruber ranged from 1 to 3%. In the open system, grain with 14 and 15% m.c. manifested low (1%) and moderate (13%) fungal invasion, respectively. However, at 16 and 17% m.c., the grain became strongly infested at 9, 12 and 15 days (61–97% infection). The reduction in grain germination was similar in both storage systems for all grain m.c., except for 17% at 12 and 15 days, since under hermetic conditions grain germination rates were higher than in the open system. Hermetic storage is an effective low cost-effective system for grain produced in the rural areas of developing countries.
An overview of information on damage caused by the larger grain borer is provided, including details of early studies examining commodities that might be attacked and the importance of LGB field infestations in relation to storage losses. In addition, examples are given from published information on the weight losses that can result from LGB infestation in maize and cassava, with case studies. Problems in applying conventional methods of loss assessment to commodities attacked by LGB are highlighted, to suggest the need to develop alternative techniques. Experiences in developing and applying novel approaches to loss assessment for LGB are reported. Examples are also given to show how loss and damage estimates have been used to describe the impact of the pest on farmers, and on local, regional and international grain trading.
Article
Abstract The International Institute of Agriculture (IITA) is among,the major,suppliers,of genetic materials,to national agricultural,research,and,extension,systems,in West and,Central Africa for the development,of improved,maize,varieties. This paper presents the results of a survey of the impact of germplasm,from IITA on maize production and food security in 11 countries, which together contain over 90% of the area cultivated to maize in West and Central Africa. Between 1965 and 1998, the public ,sectors of these ,countries ,released ,a total ,of 186 varieties while ,the private sectors released 86 varieties. In the 1990s, IITA was the major source of
Article
From 2007 through 2011 experiments were conducted and observations made in the West African country of Niger to address questions or concerns raised by farmers and extension workers about the Purdue Improved Cowpea Storage (PICS) triple bagging technology being widely disseminated in the country. When 518 triple bags stored by farmers in different villages across southern Niger were studied, the airspaces within the bags typically contained reduced levels of O2 while CO2 was increased. Bagged stored cowpea grain was much less damaged and had higher market value compared to grain for sale in the local markets. Two HDPE plastic liners rendered the system substantially airtight and improved preservation of the grain compared to a single HDPE liner. The concentrations of O2 and CO2 were similar along the length of the triple bag, in top, bottom and middle sections. Cowpea grain stored for 18 months in PICS bags retained high rates of germination. Briefly opening bags that had been closed for long periods did not affect the preservation of the grain. Treating the contents of the triple bag with phostoxin did not enhance preservation. Leaving the triple bag containing infested cowpea open for several days prior to closure increased the risk of blemishes or holes in the HDPE liners caused by cowpea bruchid, Callosobruchus maculatus (F.) adults.
Article
During the two years research 1983–1985 on traditional maize granaries in Togo, we studied three methods for loss assessment which are discussed by the FAO: the count and weigh method, the standard volume/weight method and the thousand-grain mass method.In general, between 80 and 90% of the overall losses were caused by insect feedings. Besides Prostephanus truncatus (Horn), the most important storage pests were Sitophilus zeamais (Motsch.), Tribolium spp. and Cathartus quadricollis (Guèr.). Best results were given by the count and weigh method. The significantly highest losses of dry weight (12–13%) were found after 6 months in stored hybrids. At the same time, local varieties appeared much more adapted to traditional storage methods, exhibiting losses of only 3% under the same conditions. Lowest level of losses (<1%) were observed in regularly smoked granaries in the mountain regions. The mean losses of dry weight during primary season were found to be 6.4% after 6 months, while after a storage period of 4 months during the secondary season, losses were as high as 8%. In Togo, P. truncatus was observed for the first time in spring 1984. Because of the different damage P. truncatus causes on corn, a newly developed sample weight method was examined in an additional test. After 6 months of observation, this dangerous pest caused serious losses up to 30.2%.
Article
Temperature, relative humidity (r.h.), food density, and maize (corn) cultivar (CV) influenced oviposition, development and intrinsic rate of increase of Prostephanus truncatus (Horn). The lower and upper limits for complete development were 25 and 32°C at 40% r.h.; 18 and 37°C, at 70% r.h.; and 20 and 32°C at 90% r.h. The shortest developmental periods were 25.4 ± 0.2 days in ground maize, CV Golden Beauty, at 32°C, 70% r.h., and 24.1 ± 0.2 days in whole kernel maize, CV Pride 1108, at 32°C, 80% r.h. Ground maize at a density of 750 mg/cc promoted rapid development of larvae accompanied by lower mortality and fewer malformed adults than ground maize at a density of 450 mg/cc. P. truncatus laid 430 eggs per female in blocks of maize consisting of 6-cemented kernels during 22 weeks compared with 205 eggs per female in ground maize during 15 weeks, and 36 eggs in loose maize kernels during 4 weeks. Viable eggs were laid at 18°C, 70% r.h., and 32°C, 70–80% r.h. The rate of self-multiplication and the intrinsic rate of increase per week, were: 1.94–2.24 and 0.665–0.806, respectively, at 30–32°C, 70–80% r.h. The highest rate was on field maize, CV Pioneer 3993, at 30°C, 70% r.h. The wide range of temperatures and relative humidities at which P. truncatus can develop in maize favor its establishment in tropical and subtropical regions where maize is grown and stored.
Article
Maize grain of hybrid AN 447 was: (a) infested with Sitophilus zeamais and infected with Aspergillus chevalieri; (b) infested with S. zeamais; (c) infected with A. chevalieri; and (d) grain free of insects and fungus (control); the treatments were stored for 30 days at 26°C and 15% moisture content, under hermetic and non-hermetic conditions to monitor the oxygen concentration, insect mortality, insect offspring, grain germination, and fungal growth. The oxygen was depleted to 0% after 6–9 days in those treatments infested with insects, whereas the same oxygen level was reached after 24 days in grain with the storage fungus alone. The oxygen level gradually decreased to 8.4% after 30 days in the control treatment. All insects were dead after 6 days in grain with insects and fungus, and after 12 days in grain with insects alone. A low mortality rate (1.5–3.5%) occurred in equivalent treatments of the non-hermetic conditions. Because oxygen was depleted to 0% after 6 to 9 days in those treatments infested with insects, the weevils of both infested treatments under hermetic conditions produced a significantly lower number of offspring compared with those in the non-hermetic conditions. Under hermetic conditions in grain treated or not treated with fungicide, the storage fungus A. chevalieri invaded a low percentage of grains. A low percentage of fungal invasion occurred in grain stored under non-hermetic conditions also, where the decreased moisture content did not favor fungal growth. The grain germination of those treatments stored under hermetic conditions was significantly lower than those treatments stored under non-hermetic conditions. The insects were the main oxygen consumers, followed by the fungus and finally by the grain. Under sealed storage conditions, insects and fungus combined forces to deplete the oxygen of hermetically stored maize, creating an unfavorable atmosphere for their own survival.
Article
When cowpea grain is stored in airtight containers, destructive populations of the cowpea bruchid (Callosobruchus maculatus) don't develop even though the grain put into the store is already infested with sufficient C. maculatus to destroy the entire store within a few months. The surprising effectiveness of hermetic storage for preserving grain against insect pests has long been linked with the depletion of oxygen in the hermetic container and with the parallel rise in carbon dioxide. With C. maculatus, low oxygen (hypoxia) leads to cessation of larval feeding activity, whereas elevated levels of carbon dioxide (hypercarbia) have little or no effect on feeding. Cessation of feeding arrests the growth of the insects, which don't mature and don't reproduce. As a result, population growth ceases and damaging infestations don't develop. C. maculatus eggs, larvae, and pupae subjected to hypoxia eventually die after exposures of various duration. The cause of death is desiccation resulting from an inadequate supply of water. We demonstrate that blocking the supply of oxygen interdicts the main supply of water for C maculatus. This leads to inactivity, cessation of population growth, desiccation and eventual death.
Article
Life history of immature maize weevils, Sitophilus zeamais Motschulsky. was studied at 10-40 degress C and 43-76% RH. The optimal quantity of corn for minimizing density effects and the optimal observation frequency for minimizing disturbance effects were determined at 30 degrees C and 75% RH. The quantity of corn (32-256 g) provided to five females ovipositing for 24 h did not affect duration of development, but the number of progeny produced increased asymptotically as the quantity of corn provided increased. Frequency of observation (from 1- to 14-d intervals) did not affect duration of development or number of progeny produced. Using moisture contents measured in the life history study, an equation was developed for predicting equilibrium moisture content of corn from temperature and relative humidity. Duration of immature development did not vary with sex, but did vary with test. This suggests that insect strain or chemical composition of the corn must be included as factors in a model predicting effects of environment on duration of immature development. Survival from egg to adult emergence was greatest at 95 degrees C. Sex ratio of emerging adults did not differ from 1:1. The number of multiply-infested kernels was low at all environmental conditions, and survival from egg to adult emergence in these kernels averaged 18%. Maximum daily rate of fecundity, duration of development, and number of progeny produced were optimal at 30 degrees C and 75% RH. An index of environmental suitability indicated that 30 degrees C and 75% RH was the optimal environment for growth of maize weevil populations on corn. Implications of the results for managing maize weevil populations are discussed.
Article
Mycotoxins are considered unavoidable contaminants in foods and feeds because agronomic technology has not yet advanced to the stage at which preharvest infecti