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Efficacy of the Multiple-Layer Hermetic Storage Bag for Biorational Management Of primary Beetle Pests of Stored Maize



This paper reviews the destructive effects of Prostephanus truncatus and Sitophilus zeamais on maize grain and the effectiveness of the triple-layer hermetic bag storage system as a control measure. Maize (Zea mays L.) is the most important cereal in Ghana and is the staple food for over 90% of the population. The availability and safety of this important food crop is threatened by insect pests, rodents and fungal attacks due to inappropriate storage methods. Infestation by insect pests accounts for between 20 to 50% of post-harvest losses in maize. Pesticides and other artificial gaseous techniques are no longer acceptable due to food quality and environmental related issues. In the light of the foregoing, the hermetic storage techniques have recently been revisited as a way to control insect pest and other microbial attack in maize grain. The system creates an air tight environment to rapidly exterminate insect development and suppress micro flora activity. A recent development is the invention of the triple layer hermetic bag using biodegradable plastic materials. This is being investigated to determine its efficiency as a storage technique that prevents insect attack and yields product with good food quality and market acceptability. Quantitative figures are needed about the current distribution and losses caused by insect pests especially P. truncatus and S. zeamais. There is also the need to fill the knowledge gaps and provide adequate information needed to inform decisions for the use of the use of hermetic storage technology and its further refinement.
Academic Journal of Entomology 5 (1): 47-53, 2012
ISSN 1995-8994
© IDOSI Publications, 2012
DOI: 10.5829/idosi.aje.2012.5.1.61332
Corresponding Author: P.J. Anankware, African Regional Postgraduate Program in Insect Science,
P.O. Box: 59, University of Ghana, Legon, Ghana.
Efficacy of the Multiple-Layer Hermetic Storage Bag for
Biorational Management Of primary Beetle Pests of Stored Maize
P.J. Anankware, A.O. Fatunbi, K. Afreh -Nuamah, D. Obeng-Ofori and A.F. Ansah
1 2 1,3 1,3 3
African Regional Postgraduate Program in Insect Science,
P.O. Box: 59, University of Ghana, Legon, Ghana
Forum for Agricultural Research in Africa (FARA), PMB 173 Cantonments, Accra, Ghana
Department of Crop Science, School of Agriculture,
College of Agriculture and Consumer Sciences, University of Ghana, Legon, Accra, Ghana
Abstract: This paper reviews the destructive effects of Prostephanus truncatus and Sitophilus zeamais on
maize grain and the effectiveness of the triple-layer hermetic bag storage system as a control measure.
Maize (Zea mays L.) is the most important cereal in Ghana and is the staple food for over 90% of the population.
The availability and safety of this important food crop is threatened by insect pests, rodents and fungal attacks
due to inappropriate storage methods. Infestation by insect pests accounts for between 20 to 50% of
post-harvest losses in maize. Pesticides and other artificial gaseous techniques are no longer acceptable due
to food quality and environmental related issues. In the light of the foregoing, the hermetic storage techniques
have recently been revisited as a way to control insect pest and other microbial attack in maize grain. The
system creates an air tight environment to rapidly exterminate insect development and suppress micro flora
activity. A recent development is the invention of the triple layer hermetic bag using biodegradable plastic
materials. This is being investigated to determine its efficiency as a storage technique that prevents insect
attack and yields product with good food quality and market acceptability. Quantitative figures are needed
about the current distribution and losses caused by insect pests especially P. truncatus and S. zeamais.
There is also the need to fill the knowledge gaps and provide adequate information needed to inform decisions
for the use of the use of hermetic storage technology and its further refinement.
Key words: Larger grain borer % Prostephanus truncatus % Maize weevil % Sitophilus zeamais % Triple layer
hermetic bag % IAR4D
INTRODUCTION availability of maize grains represent the difference
Maize (Zea mays L.) is an important staple crop incrop in sub-Saharan Africa. With increasing populations,
West Africa providing food and income to farmers [1]. In urbanization, changing diets and availability of new
Ghana, maize is generally harvested late to facilitatevarieties, maize consumption and production are likely to
drying. It is stored as cobs with or without the husk cover continue to increase in the region. At the same time,
either in wooden granaries, under the roof or on the floorinsect pests like the maize weevil, Sitophilus zeamais
inside the houses, or as grains in clay containers suchMotschulsky (Coleoptera: Curculionidae) and the larger
as mud silos or in polyethylene bags [1, 3]. Significantgrain borer, Prostephanus truncatus (Horn) (Coleoptera:
research and development efforts have concentrated onBostrichidae) are spreading and threatening the
increasing food production in Sub Saharan Africa (SSA),productivity of the maize based future system [4]. The
but the effects of these efforts are cut short by lack offuture spread and effects of these insect pests may
efficient post-harvest system especially those thatdepend strongly on climate change and the efficiency of
prevent deterioration and destruction from boththe post-harvest storage facilities. Research priorities
pathogens and insects. For many inhabitants of SSAshould take good cognizance of these realities and
(the smallholder farmers), changes in the quantity andconsider further development of effective options.
between a good year and a lean year. Maize is a strategic
Acad. J. Entomol., 5 (1): 47-53, 2012
Research efforts should be channeled towardsRhyzopertha dominica and Dinoderus spp. Prostephanus
developing a proper storage system to deduce post-truncatus is a pest with a high damage potential and it
harvest losses and to create a way to meet up with theposes a major problem for cob-stored maize and dry
increasing demand for maize grain [5, 6]. It is estimatedcassava chips, in all the affected countries. According to
that between 2010 and 2015, maize demand is projected to Obeng-Ofori, [8], P. truncatus can tolerate dry conditions
grow at an annual rate of 2.6% [7]. This increase inand can breed on maize with 9% moisture content. The
demand could easily be met by reducing storage lossesability of P. truncatus to develop in grain at low moisture
which could save 40% of the current production rathercontent may be one reason for its success [8]. So far,
than expanding the hectare in an unsustainable manner.about 16 African countries are reportedly affected by the
Insects attack constitutes a major cause of losses ofLarger Grain Borer [13]. According to [14], reported mean
stored maize in the tropics [8]. Recently, it has beenlosses due to LGB are around 9%, which is twice that of
reported that 9% postharvest losses are due to insect andall indigenous storage pests together. Besides
mite infestation worldwide; suggesting a need to makecontamination with the insect bodies and frass, the food
strenuous effort to control them [9]. Stored maize aresubstrate can be exposed to quinines that are released
known to be infested by a variety of insects; among them, from the thoracic and abdominal defense glands [15].
S. zeamais and P. truncatus, are the most damaging [10].
Biology and Economic Importance of S. zeamais and
P. truncatus: The developmental stages (egg, larvae andinfestation by P. truncatus and S. zeamais. The removal
pupae) of S. zeamais are all found within tunnels and
chambers bored in the grain and are thus not normally
seen. Eggs are laid throughout most of the adult life,
although 50% may be laid in the first 4-5 weeks; each
female may lay up to 150 eggs. The eggs are laid
individually in small cavities chewed into cereal grains by
the female; each cavity is sealed, thus protecting the egg
with a waxy secretion (usually referred to as an 'egg-plug')
produced by the female. Upon hatching, the larva begins
to feed inside the grain, excavating a tunnel as it
develops. There are four larval instars in ‘English wheat
at 25°C and 70% RH. Pupation occurs after about 25 days,
although development periods are extremely protracted at
low temperatures. The newly developed adult chews its
way out, leaving a large, characteristic emergence hole.
Total development periods range from 35 days under
optimal conditions to over 110 days in unfavorable
conditions. The actual length of the life cycle also
depends upon the type and quality of grain being infested
[11]. In stored maize, heavy infestation by P. truncatus
and S. zeamais may cause weight losses of as much as 30-
40% [12]. S. zeamais has been found to be amongst the
most important pests of maize in a number of studies; in
steel silos, in sacks and barns throughout Ghana.
The larger grain borer, P. truncatus Horn is thought
to be a native of Central America. It was first described by
Horn in 1878 who named it Dinoderus truncatus. It is 3-4
mm long, cylindrical and dark in colour. The flattened
ends of the wing and the ridges give P. truncatus a very
square-cut end, thus distinguishing it from other
bostrichids known to attack stored products i.e
Control Strategies for P. truncatus and S. zeamais:
Good store hygiene plays an important role in limiting
of infested residues from last season's harvest is
essential. Aeration dramatically reduces the numbers of
insects compared with population levels in non-aerated
Zea mays genotypes resistant to S. zeamais have
been evaluated in the field in Benin [9]. Genetic variability
for resistance to S. zeamais in domestic US maize
germplasm has been identified. In Brazil, tests were carried
out with maize cultivars to evaluate the attractiveness and
oviposition preference of S. zeamais. In the case of the
LGB, the phenolic acid content of maize grain, especially
that of para-coumaric acid has been shown to be
important [16].
Management of agricultural pests over the past half
century has been largely depending on the use of
synthetic chemical pesticides for field and post-harvest
protection of crops [17].
Grain may be protected by the admixture of
insecticide. Research in Togo estimated the toxicity of
deltamethrin to a number of resistant and susceptible
populations of S. zeamais in traditional maize stores. The
toxicity of deltamethrin, fluvalinate, chlorpyrifos-methyl,
etrimfos and malathion against S. zeamais and topical
application bioassays of DDT has also been evaluated
[18].P. truncatus can be controlled chemically by using
permethrin, deltametrin and a combination of pyrethriods
with phosphorus acid ester compounds [19]. Even though
chemicals are generally quick acting against pests,
there are serious limitations to their use. Misuse or
overuse of chemicals have serious repercussions, such
Acad. J. Entomol., 5 (1): 47-53, 2012
as the development of resistance, pollution of theThe Hermetic Storage Technology: Hermetic simply
environment, effect on non-target organisms, foodmeans ‘airtight’. The origin of hermetic storage dates back
poisoning, among others [20]. to antiquity. Hermetic storage (HS) technology has
Dry heat treatment has been found to be an effectiveemerged as a significant alternative to other methods of
control against all developmental stages of S. that protect commodities from insects and molds.
Local farmers in northern Ghana usually use sun-dryHermetic storage is based on the principle of generating
insect infested maize to kill larvae and to drive awayan oxygen-depleted, carbon dioxide-enriched interstitial
adults. Treatment with 15% carbon dioxide and 5%atmosphere caused by the respiration of the living
oxygen controlled the insects in 10 days. Carbon dioxideorganisms in the ecological system of a sealed storage
at concentrations of 50% and 60% killed all life stages ofstructure [9, 24, 25, 26]. Pioneering modern hermetic
the weevil after 10 days of exposure. Under sealed storage storage, [27, 28] has resulted in the broad use of safe,
(hermetic) conditions in maize, insects and fungi bothpesticide-free hermetic storage suitable for many
deplete the oxygen supply, creating an unfavorablecommodities and seeds, particularly in hot, humid climate.
atmosphere for their own survival [11, 21]. Hermetic storage takes three distinct forms. 1) “Organic-
A good number of plant extracts are toxic to adults of Hermetic storage”, relies on the metabolic activity and
S. zeamais and P. truncatus. Garlic oil is toxic to adultsrespiration of insects, microflora and the commodity itself
and oils of coconut, sunflower, sesame and mustard,to generate a modified, non-life sustaining low oxygen
alone and in combination with eucalyptol, eugenol oratmosphere, 2) “Vacuum-Hermetic Fumigation” (V-HF) -
camphor have been found to be toxic to S. zeamais inuses a vacuum pump to rapidly create a very low pressure
wheat and maize-treated grains [22]. Botanicals currentlyatmosphere for accelerated disinfestations of non
constitute 1% of the world’s insecticide market, despitecrushable commodities through asphyxiation; and 3)
the knowledge that plants constitute an effectiveGas-Hermetic Fumigation (G-HF) uses an external gas
alternative to regular insect control agents. Other plantsource (usually CO ) for crushable commodities, such as
extracts have exhibited toxicity to S. zeamais. Thesedried fruit, prior to shipment [29].
include: Ocimum suave, Ocimum kenyense, Ocimum A more recent but increasingly popular form of
kilimandscharicum [23]; Tagetes minuta, Capsicumhermetic storage system is the triple layer bag [30]. This
annuum etc. system utilizes a thin, transparent and low permeability
The effect of different isolates and formulations ofco-extruded multi layer plastic as a liner to a conventional
Beauveria bassiana on S. zeamais in stored maize arejute or polypropylene bag. The triple bag consists of 2
reported. The bionomics of the pteromalid parasitoidlayers of polyethylene bags which are expected to be as
Lariophagus distinguendus and its controlling effect onhermetic as possible and both are included in a protective
S. zeamais has been evaluated. L. distinguendus waspolypropylene woven bag [30]. Prior to the introduction
found to have five generations each year in theof these bags in West Africa, farmers lacked appropriate
laboratory, with final-instar larvae of the parasitoid over-polyethylene bags and so they often use insecticides or
wintering in larvae of S. zeamais. The parasitoidcombination of insecticides with solar heating for grain
Theocolax elegans has also been recorded to attackstorage [31]. Triple-bagging prevents the development of
S. zeamais. mycotoxins such as aflatoxins and ochratoxin [27, 32]. It
The histeride beetle Teretrius nigrescens has beenalso prevents quality loss due to increase of Free Fatty
identified as the most effective natural antagonist ofAcids (FFAs) in the low oxygen environment [24, 33, 34].
P. truncatus [8]. It feeds on eggs, larvae and sometimesFinally, the method is suitable for long-term storage of
even on adults of P. truncatus. T. nigrescens thoughmaize, rice and high value commodities such as coffee,
effective, has not been able to entirely eradicate the graincocoa, peanuts and spices in addition to permitting long-
borer. Besides, it is even feared that the T. nigrescens may term seed preservation without refrigeration [35, 36]. The
even be a pest in disguise. There is even some evidencetriple-bagging technology was disseminated in Cameroon
that T. negriscens imagines can feed on plants with highin the 90’s [37]; it has also been used in Niger, Burkina
starch content, such as maize, wheat, sorghum andFaso and Northern Nigeria for successful storage of
cassava. It is for this reason that the search for othercowpea under the Purdue University PICs project [31, 38].
control measures especially those intended to mitigateThe triple-bag technique can be easily adopted by
post harvest losses and to complement T. nigrescensfarmers since low-grade polyethylene bags allowing low
became necessary; hence the hermetic storageoxygen permeability is available and affordable.
technology. Furthermore, polyethylene bag storage is a flexible
Acad. J. Entomol., 5 (1): 47-53, 2012
technique that fits with the West Africa commoditiesawareness about the efficacy and cost-effectiveness of
trade [39]. Triple layer bag capacities range from 5kg tothe three layer bag among farmers and stimulate
1,000 kg, with 43-60 kg capacity being the most common. information exchange between stakeholders. This in turn
At the individual small farm level they can be protectedcould result in the identification/realizations of farmer’s
from rodents by storage in empty 55-gallon drums. Byinterest and innovations. Adult learning tools such as the
preventing the entry of water vapor into a hermeticallyFarmer Field School developed by FAO, or Participatory
sealed container, adequately dried commodities areLearning and Action Research (PLAR) [41] and the use of
protected from external humidity, preventing a rise in their learning videos [42] would also be effective methods to
moisture content beyond their critical moisture level ofdemonstrate to farmers how effective removal of air and
14% [40]. Many studies in various countries have showntying of the triple-bags can be used to increase
that triple-bagging maintains germination of 85% or more effectiveness and avoid detrimental effects by puncturing.
for periods up to 9 months, while conventional storage inA more effective way to communicate this technology
jute bags reduces germination down by14% to 76% within would be its integration within the innovation platforms
3 months [14]. This has led to the adoption of hermeticestablished within the Integrated Agricultural Research
storage by some leading seed producers. for Development Concept (IAR4D). This concept will
Research Needs: Many knowledge gaps need to be filled farmers on the innovatiotion platform. The suitability of
in other to support farmer’s decision with respect tothe IAR4D concept has been reported elsewhere [43].
management of beetle pests on stored maize. More
quantitative figures are needed about the currentCONCLUSION
distribution of beetle pests (especially S. zeamais and
P. truncatus), the importance of individual species andThe use of hermetic storage is now becoming
the extent to which they are responsible for hugewidespread using modern low permeability plastic
post-harvest losses in the sub-region. This information,materials which are light-weight, which can be used
combined with historical data and future predictions ofindoors or outdoors, have long lifespan and are now, in
maize production and long-term storage ability, as well as the case of triple layer bags, transportable when full.
data on the economic importance of different beetle pest’s Pesticide-free three layer bag technology has already
species could provide more solid evidence on which tobeen found suitable for a number of markets. This is
base priority setting for concerted research andespecially true where conventional storage, such as in hot
development efforts on triple-bagging technology in thehumid climates, fails to adequately protect the stored
sub-region. Current knowledge of triple-bagging and itscommodity for the desired time and this results in large
availability is very limited. Why for example, is triple-losses in quantity and quality [35, 36]. Studies show that
bagging in use in South America and Asia for so long and hermetic storage of cowpea for 8 months in triple layer
not in common usage in Africa? Then again why hasbags maintains constant moisture and germination rates
triple-bagging been proven effective in controlling the[38].
cowpea beetle Callosobruchus maculatus F. (Coleoptera: Triple-bagging is a sustainable, cost effective, user-
Bruchidae) and still not been used in managing majorfriendly and environmentally benign technology that
pest of maize which is rather a staple food crop in themakes the use of pesticide and fumigants in post harvest
sub-region. Further studies should include investigationsand seed storage unnecessary. The technology has
on effects of climate and increased temperatures on thealready been adopted for the protection of many different
effectiveness and longevity of the three layer hermeticcommodities in quantities ranging from that of
bag. The development of biodegradable triple-layer bagsconventional grain bag size to many thousands of tones.
that combines different defense mechanisms with otherApplications of triple-bagging technique is likely to
desirable traits such as resistance or tolerance againstexpand even more rapidly in the future, as the available
rodents and other biotic and abiotic factors should alsoforms of hermetic storage continue to increase and more
be considered. More detailed information on theusers experience and understand the advantages of this
effectiveness of the triple bag in managing common“green” technology. By a commitment to community
storage insect pests and cost-effectiveness of its usageengagement with local traditional leaders and district
needs to be well communicated to the final consumerscouncils, researchers and extension workers, the triple-
(farmers, middlemen/women and market women).bagging technologies will grow to take over the less
Participatory approaches and videos could help to raiseefficient indigenous storage systems.
often achieve a hundred percent technology adoption by
Acad. J. Entomol., 5 (1): 47-53, 2012
ACKNOWLEDGEMENTS 9. Vachanth, M.C., K.M. Subbu Rathinam, R. Preethi
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... Permeable packages are those which allow a greater exchange of water vapour between the seeds and the atmospheric air, therefore, they are typically recommended for shorter storage times, however this packaging should preferably be located in dry places (Anankware et al., 2012). On the other hand, semipermeable packaging offers high resistance to water vapour exchange and therefore, the moisture content of the seeds in the initial stage of storage should be lower than recommended (Bartosik, 2012). ...
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The use of silo and raffia bags for the temporary grain storage has been increasing in recent years. However, the methods for monitoring a stored product are limited to visual inspections and sampling. Thus, this research aimed to real‐time equilibrium moisture content monitoring to predict grain quality of corn stored in different conditions in silo and raffia bags using wireless sensor network prototype, Internet of Things (IoT) platform, and neural network algorithms. Experiments were conducted using corn grain with two initial water contents of 13% and 18% (w.b.), three storage environments with temperatures of 30, 23, and 17°C, and two types of packaging, that is, silo and raffia bags, for a 3‐month storage evaluation. During the monitoring of stored grain, variations in equilibrium moisture hygroscopic content were observed, which inferred changes in the corn quality. Water contents of 13% under a storage condition of 17°C showed the highest quality results, whereas storage in silo bags with water contents of 13% and 18% showed no differences at 23°C; however, at a temperature of 30°C, the grain suffered a high level of deterioration. The storage time influenced the reduction of grain quality for all factors. The physicochemical quality prediction results indicated a high coefficient of determination of the trained models, presenting itself as a promising perspective, mainly in developing embedded technologies for monitoring and predicting the qualitative variables of grain stored in silo and raffia bags. Practical Applications The application of sensor technology and the Internet of Thing (IoT) to monitor the temperature and relative humidity of intergranular air in real time for the determination of equilibrium moisture content became possible to predict the physical and physicochemical quality of grains stored in bag silos and raffia bags using artificial neural networks (ANN) algorithms. The results obtained were satisfactory and can replace the punctual sampling of the grains mass stored in hermetic packages. The application of a set of technologies possible to monitor the grain quality in real time and predict the grain storage time in bag and raffia silos to reduce losses.
... Permeable packages are those which allow a greater exchange of water vapour between the seeds and the atmospheric air, therefore, they are typically recommended for shorter storage times, however this packaging should preferably be located in dry places (Anankware et al., 2012). On the other hand, semipermeable packaging offers high resistance to water vapour exchange and therefore, the moisture content of the seeds in the initial stage of storage should be lower than recommended (Bartosik, 2012). ...
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Superior agricultural yields are obtained from seeds which have a high physiological potential, these are conserved in the post-harvest stage. Thus, it is crucial to implement post-harvest projects with appropriate technologies related to the equipment used and the control of operations. This article presents a review of the technical-kinetic developments in the area of the technology of processing post-harvest soybean seeds, with a particular focus on the evolution and current circumstances of the sector. The findings from this research reveal significant technological advances in the drying, processing and storage of seeds at different levels and in various areas of soybean production. In drying systems, temperatures of up to 40°C are recommended, while seed batches must remain static in drying chambers. When processing and standardizing seeds, it is recommended that low-moving equipment and abrupt contacts with mechanical systems, such as pneumatic and gravity separators, be employed to minimize dropping and contact with seeds. In soybean storage, the applications of technologies that can control temperature and relative humidity, and also maintain the storage moisture content in a hygroscopic balance are recommended. The storage of seeds in coated big bags and artificial cooling; a controlled and modified atmosphere serve to preserve essential seed qualities. This review concludes that over the years, there has been a reduction in the cumulative losses due to post-harvest processes.
... The type of storage is another factor that affects the germination capacity and vigor of stored seeds. Grains stored in different forms of HS containers have been shown to maintain their germination potential higher and longer than those in conventional non-hermetic counterparts (Anankware et al., 2012;Bakhtavar et al., 2019;Ellis and Hong, 2006;Freitas et al., 2016;Sudini et al., 2015). Table 2 shows the comparisons of hermetic and non-hermetic storage of grains on seed germination. ...
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
... The technology functions by creating a modified atmosphere around the grains through physical and biological means which results in depletion of oxygen and increased carbon dioxide levels. The depleted oxygen level leads to low insect activity and survival in the stored grain (Anankware et al., 2012). In recent years, the technology has received significant attention from researchers, development agencies, governments and the private sector as a means of safeguarding stored grain (Murdock et al., 2003). ...
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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.
... 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. Hermetic storage bags are designed in varying capacities suitable for the storage needs of smallholder farmers [29]. ...
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.
... Airtight storage is based on the rule of generating oxygen drained, carbon dioxide enhanced interstitial atmosphere caused by the respiration of the living organisms in the biological system of a sealed storage structure (Vachanth et al., 2010). Airtight storage is an alternative to other methods of storage that ensures commodities from insects and molds (Anankware et al., 2012). Oxygen and dampness impermeable bags protect maize and sorghum superior than traditional storage structures and polypropylene sacks. ...
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Proper postharvest storage of grain is more important than the intensive and extensive farming in securing food for a nation, because losses are not only a waste of food but also represent a similar waste of human effort, farm inputs, livelihoods, investments and scarce recourses such as water. Postharvest losses of stored crops are very common problems in developing countries, like Ethiopia, which has a negative impact on the food security program. This is because poor storage systems make grains vulnerable to attacks from insect and rodent pests, which lead to a considerable amount of losses. In order to help and address the problem of small scale agriculture towards development into a modern production sector, strengthening the postharvest sector or system is essential. It is important to understand postharvest losses in both quality and quantity since it is related to lost income and /or value of commodities produced and hence part of measure and primary concern to bring a food secured nations through modern agricultural production. Postharvest quantity and quality loss of cereal grains in developing countries appears to be initiated mostly at farm-level, so the potential remedies for the problem are needed at the same level. The objectives of this review are, therefore, to assess the available literatures on the postharvest losses of stored grain in an attempt to identify priority areas of the problem; to identify the causes of losses of stored crops in order to avoid the causes for the reduction of losses; and to identify the possible strategies that can reduce losses and maintain quality of the grain during the storage period.
... Insect pests of stored products cause serious post-harvest losses in various crops (cereals, legumes, dried fruits and vegetables) and reduce their quantity and quality (Anankware et al. 2012). In developing countries, about 15% of grains are annually damaged by insect pests during storage (Kumar and Kalita 2017). ...
In the present study, repellent activity of three plant essential oils (EOs) [anise (Pimpinella anisum L.), eucalyptus (Eucalyptus camaldulensis Dehn.) and peppermint (Mentha piperita L.)] and their major components (trans-anethole, 1,8-cineole and L-menthol, respectively) was evaluated at five concentrations (3.6, 7.1, 14.3, 28.6 and 57.1 µl/l air) through Y-tube olfactometer against the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), under laboratory conditions. The binary (1:1) and ternary (1:1:1) combinations of the EOs and/or components were also evaluated for their possible combination effects (synergism, antagonism and additive effect). The results showed that all the EOs and components tested, both alone and in binary and ternary combinations, had a repellent activity on adult S. oryzae. However, repellency was concentration dependent (P = 0.05). None of the combinations tested had a statistically significant influence on the repellence against adult S. oryzae (P = 0.05). Based on the estimated RC50 (the concentration required to obtain 50% repellency) values, binary and ternary combinations generally had lower RC50 values, indicating that they were more repellent to S. oryzae than the single application of EOs or components, except for anise EO and 1,8-cineole. Considering the combination index (CI) values, most of the binary and ternary combinations showed synergistic effects (CI < 1), while some of them exhibited additive effects (CI = 1). However, no binary or ternary combination showed an antagonistic effect (C > 1). Overall results suggest that EOs and their components may help prevent the rice weevil infestations and can be used to develop new products that meet expectations.
... Several methods have been used in the preservation of maize [12][13][14][15][16] some of which are drying and storage crib; mud or cement-plastered basket; brick bin; ferrocements bin (Ferrumba); postcosecha galvanized steel silos; in the modern-day technology, refrigeration system also can be used because it can be manipulated to give various conditions. Charles and Rogers [17] observed that overnight storage of fresh maize in wagon or truck can have a marked effect on their future storability. ...
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Aims: In this research project, a refrigeration system that will preserve the quality of fresh maize was developed. Study Design: Design of refrigeration system. Place and Duration of Study: Department of Industrial and Production Engineering, Federal University of Technology, Akure, Ondo State, Nigeria, between August 2017 and February 2018. Methodology: The designed system consists of a cooling cabinet, compressor, condenser and an evaporator. The cabinet was designed to store up to 15 kg of maize and a compressor of 1/6 hp was used. The equivalent condenser and evaporator were selected with an equivalent expansion valve. R134a was used as the refrigerant. The cabinet walls were fabricated from mild steel (outside wall), stainless steel (inner wall) and glass wool (insulator). Results: The fabricated system stores fresh maize above its freezing temperature of -1ºC. The system operating temperature ranges from -4 to 2.5ºC with a relative humidity of 90 to 95% for eight hours. Conclusion: The fresh maize was stored for ten days without noticeable changes in the physical appearance and taste of the maize.
In recent decades, at Ukrainian farms and grain-processing enterprises, the technology of storing grain in silo bags has become widespread. In this type of storage, anaerobic conditions are created due to the physiological respiration process, which ensures extended shelf life of freshly harvested grain. This, in turn, allows the use of low-power processing equipment for post-harvest grain processing, which is especially important for wet and moist maize as it requires powerful grain dryers. The article presents the results of a study of the effect that the initial moisture content of maize grain, the temperature and the duration of its storage under anaerobic conditions have on the Falling Number, one of the quality parameters depending on the amylase activity of the grain. The object of the study was grain samples of freshly harvested (in 2017) dent maize, the hybrid DKC 3705, with the average moisture contents 14%, 21%, and 28%, stored under anaerobic conditions for 3 months at temperatures of +18°C, +11°C, and +4°C. The Falling Number was determined by the standardized Hagberg-Perten method on a ПЧП-7 instrument (“Falling Number Apparatus”). Based on the results obtained, histograms of the kinetics of Falling Number changes have been constructed, the analysis of which made it possible to establish patterns of the changes in the Falling Number depending on the moisture content of the grain and the duration of its storage at different temperatures. It has been shown that in the maize grain samples with the initial moisture content 14%, regardless of the temperature conditions during storage for 3 months, there is a steady tendency to a gradual decrease in the Falling Number. In the maize grain samples with the initial moisture content over 14%, at the beginning of storage, there is a period of an increase in the Falling Number, the intensity of which depends on the initial moisture content of the grain and the temperature conditions of its anaerobic storage. After the completion of post-harvest maturation processes in freshly harvested maize grain, its further storage leads to a decrease in the Falling Number. To summarize the experimental data, a nonlinear empirical equation is suggested to describe the patterns of changes in the Falling Number depending on the factors studied: the moisture content of maize grain, the temperature conditions and duration of storage. Considering that the value of the Falling Number is determined by the activity of the amylase complex of the grain, it can be used as an express method of monitoring the state of grain stored in silo bags.
Conference Paper
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Two technologies were presented that provide alternatives to methyl bromide fumigations. They are both based on flexible PVC liners that enclose and seal the commodity to be treated. In the first case a pressure of 50±5 mm Hg is applied to control insects in granular or farinaceous commodities. This was exemplified by treatment of imported soybeans to control moth infestations. Monitoring and handling procedures were described together with a cost analysis. In the second case, narcissus bulbs for export serve to demonstrate how geophytes can be disinfested by harbouring their metabolism to rapidly produce a hypoxic atmosphere within the sealed liners. INTRODUCTION The 2002 report of the methyl bromide technical options committee of the UNEP includes in Chapter 5 a detailed list of MB alternatives for the treatment of durable products and structures developed by various research groups to find MB alternatives. These are destined to help the non article 5 countries to meet the deadline of January 2005, and also to direct the activities of article 5 countries who are obligated to reduce MB usage over the coming years. However, the list provided is far from comprehensive, and in particular there is an absence of treatments that could be used as substitutes for MB in quarantine treatments. Critical use nominations (CUN) have been submitted to the Technology and Evaluations Panel for the year 2005, but even where these exemptions (CUE) have been accepted, they are temporary, and nominations must be renewed on an annual basis, with decreasing likelihood that they will be received favorably. Agricultural producers and food manufacturers outside EU countries and those within the EU, recognise the urgent need to find MB alternatives in order to be able to continue trading with and within the European community. In Israel, where a major part of agricultural production is destined to the EU community, the critical stage of the MB phase-out has led Israeli researchers, in cooperation with local agricultural and food manufacturing industries to take steps to maintain their obligations and conform with international regulations.
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Under humid and warm conditions harvested grains are susceptible to molding and rapid deterioration. Therefore, they should be dried to safe moisture levels that inhibit the activity of microorganisms. Drying to these moisture levels is not economical for farmers in developing countries. Preservation of grains at intermediate moisture levels under hermetic storage conditions could be feasible and economical in warm and moist climates.The purpose of the current study was to examine the effect of various moisture contents (m.c.) on the quality of maize grains in self-regulated modified atmospheres during hermetic storage.Maize at 14, 16, 18, 20 and 22% m.c. was initially conditioned for 28 days in tightly wrapped plastic bags and then stored in sealed containers at 30 °C for up to 75 days. Carbon dioxide produced within the containers replaced the oxygen. As the m.c. increased the time for O2 depletion shortened, from 600 h at 14% m.c. to 12 h at 22%. The maize at 20 and 22% m.c. exhibited the highest dry matter (DM) losses, the lowest germination rates and the highest yeast and bacteria counts. The major fermentation product in the hermetically sealed maize was ethanol (0–5 g kg−1 DM), along with lower concentrations of acetic acid (0–1 g kg−1 DM).The results obtained from the in vitro experiments indicate that maize at the tested moisture levels can be stored satisfactorily under sealed conditions in which self-regulated atmospheres provide protection against microflora damage. Further large-scale trials will be needed to evaluate the economic feasibility of storing high-moisture maize.
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Aflatoxin level in 300 farmers’ stores in four agro-ecological zones in Benin, a west African coastal country, were determined over a period of 2 years. At sampling a questionnaire was used to evaluate maize storage practices. Farmers were asked what storage structure they used, their storage form, storage period, pest problems in storage and what was done against them. Beninese farmers often changed their storage structures during the storage period, transfering the maize from a drying or temporary store to a more durable one. Most of the farmers complained about insects damaging stored maize. Often, storage or cotton insecticides were utilized against these pests. Regression analysis identified those factors that were associated with increased or reduced aflatoxin.Maize samples in the southern Guinea and Sudan savannas were associated with higher aflatoxin levels and the forest/savanna mosaic was related to lower toxin levels. Factors associated with higher aflatoxin were: storage for 3–5 months, insect damage and use of Khaya senegalensis-bark or other local plants as storage protectants. Depending on the agroecological zone, storage structures that had a higher risk of aflatoxin development were the “Ago”, the “Secco”, the “Zingo” or storing under or on top of the roof of the house. Lower aflatoxin levels were related to the use of storage or cotton insecticides, mechanical means or smoke to protect against pests or cleaning of stores before loading them with the new harvest. Fewer aflatoxins were found when maize was stored in the “Ago” made from bamboo or when bags were used as secondary storage containers.
The invasive storage pest, the larger grain borer (LGB) Prostephanus truncatus (Horn), was introduced into the maize-deficit, semi-arid areas of the eastern region in Kenya in the early 1980s. In spite of containment efforts and the introduction of the predator Teretrius nigrescens Lewis from Mexico, LGB has spread to the main maize production zone in western Kenya during the past five years. The present work presents results from a 28-month monitoring effort of LGB and its predator, using pheromone traps at five locations along an east-west transect across Kenya. LGB occurred in all regions with highest trap catches in the high potential maize production zones in Western Kenya. T. nigrescens had not spread to western Kenya and trap catches were very low and mostly zero in Eastern Kenya, even in the area where it was released during the 1990s, suggesting that it became locally extinct after initial establishment. LGB flight activity was closely related to relative humidity, temperature and vapour pressure deficit. A model based on climatic factors accurately predicted seasonal trends of LGB flight behaviour in Kakamega and Mombasa but not in Kitale and Thika. It was concluded that models that rely on the direct effect of climate cannot predict LGB flight accurately enough to allow assessment of the impact of T. nigrescens on a regional basis. It is suggested that other factors such as the availability of stored grain and thus the indirect effect of climate via enhanced or reduced crop production play a major role in the flight activity of LGB and T. nigrescens.
Plant oils (cottonseed, soybean, corn, groundnut and palm) at different dosages were evaluated in the laboratory for their ability to suppress the populations ofCryptolestes pusillus andRhyzopertha dominica in maize and sorghum. Exposure of adults of both beetle species to grains treated with 10 ml/kg of the different oils induced 100% mortality within 24 h. A dose of 5 ml/kg of each oil significantly decreased the progeny produced byR. dominica. Complete protection was achieved on grains treated with 10 ml/kg. These oils also repelled the adults of both species. Percentage weight loss caused byR. dominica in grains treated with 5 ml/kg and 10 ml/kg levels were significantly lower than in untreated grains. Oil treatment did not affect the germination of, or water absorption by, maize and sorghum grains compared with untreated grains. The potential use of plant oils in the management of insect pests in traditional grain storage is discussed.
Nootkatone is a natural sesquiterpene ketone that shows insecticidal activity against insects and ticks. Its contact toxicity and repellency against two major stored-product insect pests, maize weevil (Sitophilus zeamais Motschulsky) and rice weevil [Sitophilus oryzae (L.)], were investigated in the current study. Contact toxicity was evaluated using a no-choice test with treated filter paper, while repellency was evaluated using a choice test with treated corn (for maize weevils) or wheat (for rice weevils). Nootkatone showed low contact toxicity (ranging from 0 to 51%) against the two weevil species at the tested concentrations (ranging from 11.58 μg/cm2 to 1158.08 μg/cm2) on filter papers. In choice tests, corn treated with 0.10% or higher and wheat treated with 0.5% nootkatone or higher had significantly fewer maize or rice weevils compared with the solvent only treated control, indicating a repellent effect. The repellency percentage ranged between 46.3 and 93.1% against maize weevils and 39.2–67.2% for rice weevils.
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