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Grain legume storage in developing nations

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Grain legume storage in developing nations

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Callosobruchus maculatus Fab. (Coleoptera: Chrysomelidae) is a major pest of stored cowpea in West Africa, responsible for significant weight losses and grain deterioration during storage. Biological control of this pest using its native larval (Dinarmus basalis) and oophagous (Uscana lariophaga) parasitoids is currently investigated. The present study aims to assess into experimental storage systems the effects of five options of releasing U. lariophaga and D. basalis, alone or in combination, on the populations of C. maculatus in comparison with a control without any parasitoid. The combined releases of the two parasitoid species prevented the increase in C. maculatus numbers better than the release of a single parasitoid species. Each parasitoid species behaved differently when alone versus in combination. Thus, D. basalis had a higher development and rates of parasitism when it was alone, whereas the opposite was observed in U. lariophaga, whose parasitism activity seemed to be stimulated by the presence of D. basalis. After 150 days of storage, the cowpea seed losses were estimated to be significantly lower (9–13%) in all parasitoid combination treatments instead of 31% and 62% in single parasitoid treatments and the control, respectively. Our results suggest that combined releases of both parasitoids can additively control the pest and maintain cowpea quality over 5 months of storage. Further studies should precise the optimal densities of each species to be released without additional introductions throughout the storage period. Interactions between D. basalis and U. lariophaga are still poorly known and will require in-depth scientific investigations.
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Synthetic insecticides were evaluated for their grain protectant efficiency against Callosobruchus chinensis Linnaeus in stored black gram. Among the different insecticides, deltamethrin 2.8 EC, cypermethrin 10 EC and spinosad 45 SC, all at 4 ppm found more effective. These insecticides recorded significantly lower number of adult's emergence (< 1.81), higher half-life values (>183.44 days) and higher gross persistency (7558.33 to 6627.30). In addition, insecticide did not effect on the germination.
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Stored product insects feed on grains and processed commodities manufactured from grain post-harvest, reducing the nutritional value and contaminating food. Currently, the main defense against stored product insect pests is the pesticide fumigant phosphine. Phosphine is highly toxic to all animals, but is the most effective and economical control method, and thus is used extensively worldwide. However, many insect populations have become resistant to phosphine, in some cases to very high levels. New, environmentally benign and more effective control strategies are needed for stored product pests. RNA interference (RNAi) may overcome pesticide resistance by targeting the expression of genes that contribute to resistance in insects. Most data on RNAi in stored product insects is from the coleopteran genetic model, Tribolium castaneum, since it has a strong RNAi response via injection of double stranded RNA (dsRNA) in any life stage. Additionally, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology has been suggested as a potential resource for new pest control strategies. In this review we discuss background information on both gene disruption technologies and summarize the advances made in terms of molecular pest management in stored product insects, mainly T. castaneum, as well as complications and future needs.
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Bruchids are the most notorious pest that can devastate the entire seed lots of food legumes in storage. The extent of damage varied with legume crops and bruchid spp. Several options including insecticidal pesticide application are currently available to check bruchid infestation. However, development of cultivar with adequate level of host plant resistance can be cost effective, durable and eco-friendly approach. In this pursuit, the author presented a detailed review of the insect life style, screening technique, source and mechanisms of resistance, mode of inheritance and novel breeding strategies including genetic transformation and use of molecular and seed protein markers in marker aided selection. Keywords: Bruchids, food legumes, source of resistance, inheritance, breeding strategy.
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Bruchus pisorum (L.) is one of the most intractable pest problems of cultivated pea in Europe. Development of resistant cultivars is very important to environmental protection and would solve this problem to a great extent. Therefore, the resistance of five spring pea cultivars was studied to B. pisorum : Glyans, Modus; Kamerton and Svit and Pleven 4 based on the weevil damage and chemical composition of seeds. The seeds were classified as three types: healthy seeds (type one), damaged seeds with parasitoid emergence holes (type two) and damaged seeds with bruchid emergence holes (type three). From visibly damaged pea seeds by pea weevil B. pisorum was isolated the parasitoid Triaspis thoracica Curtis (Hymenoptera, Braconidae). Modus, followed by Glyans was outlined as resistant cultivars against the pea weevil. They had the lowest total damaged seed degree, loss in weight of damaged seeds (type two and type three) and values of susceptibility coefficients. A strong negative relationship ( r = −0.838) between the weight of type one seeds and the proportion of type three seeds was found. Cultivars with lower protein and phosphorus (P) content had a lower level of damage. The crude protein, crude fiber and P content in damaged seeds significantly or no significantly were increased as compared with the healthy seeds due to weevil damage. The P content had the highest significant influence on pea weevil infestation. Use of chemical markers for resistance to the creation of new pea cultivars can be effective method for defense and control against B. pisorum.
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The common bean, Phaseolus vulgaris (L.), is one of the most important sources of protein worldwide, and Latin America is one of the recognized centers of diversity of this species. However, storage of this product after harvest is not feasible because of bruchid attacks. This study determined the accumulated normalized rate of emergence and the daily emergence rate of Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae: Bruchinae) in five landrace varieties of common bean (BRL 01, SNA 01, RDR 01, RBC 01, and RBC 13) that occur in southwestern Amazonia. These varieties were selected for this study because they are well-distributed throughout the Amazonian communities. Beans of each variety were infested with 50 unsexed adults, and the insects were removed 13 d after beginning the bioassays. The adult progeny obtained from the feeding substrate were counted and removed every other day after the first emergence, until the end of the emergence period. Differences were observed in the calculated rates of development; however, the time required for development and emergence of the insects was independent. Of the five varieties of bean investigated, we observed that the RDR 01, BRL 01, and SNA 01 cultivars are resistant to Z. subfasciatus; the results indicate that the use of these three varieties can reduce problems associated with bruchid attacks and enable storage of the product after harvesting.
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The prehistoric development of food storage represents a major evolutionary transition, one potentially more important than the initial domestication of plants. Researchers, however, have yet to really deal with some of the critical practical questions related to the materiality of food storage and decision-making. Drawing upon experimental research this paper seeks to identify and model some of the critical interconnections between anticipated food loss due to spoilage, storage decision-making and the need for people to store food for multiple years. Building on this foundation, and echoing ethnographic, ethnoarchaeological and archaeological research, this study argues that the concept of storage and surplus is underdeveloped and that in many cases the storage practices of prehistoric sedentary people do not reflect a food surplus so much as normal storage. Turning to a case study of changing Near Eastern Neolithic grain storage practices, this research argues that from the Natufian through Neolithic periods people increasingly relied upon cultivated domesticated plants and food storage. This required people to expand their use of preexisting technology, such as plaster for lining storage features, to store sufficient amounts of food to overcome seasonal shortages, potential crop failures and minimise food spoilage due to a range of biological agents. Tracking shifts through time, the results of this study suggest that it is only with increased scale of food storage in the later stages of the Neolithic that we may see a materialization of a food surplus.
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The bruchid, Callosobruchus analis L., is a common storage insect pest of leguminous pulses including lentil (Lens culinaris Medikus). This study was conducted to document relative resistance and susceptibility differences among the eight lentil genotypes against C. analis. Feeding preference, weight lost after feeding, frass weight obtained, reproduction and development time of the bruchid pest, thickness of the outer seed coat and percentage germination were measured to determine the reaction of lentil genotypes. The results showed that none of the genotypes screened was completely free from bruchid infestation. Seeds of genotype AEL-49/20 were least infested and displayed relatively tolerant response; conversely, genotype AEL-23/40 harboured the maximum infestation and was highly susceptible. The remaining six genotypes, Matiary-S, AEL-57/50, M-85, ICARDA-8, AEL-28/40 and M-93 were categorized as intermediate (moderate resistant or moderate susceptible) to the attack of bruchids. Significant (P ≤ 0.05) variations existed among the lentil genotypes with respect to seed coat thickness (from 19 to 39 µm), playing an important role in imparting resistance. Germination test of tolerant genotype AEL-49/20 showed 91 % emergence potential. The results emphasize the importance of resistance development to maximize the protection of L. culinaris against C. analis.
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Essential oils extracted from native aromatic plants are currently considered as promising alternatives to protect stored cowpeas from pests in West Africa. The optimal application of essential oils has not yet been investigated. One key factor to consider would be the practical considerations of cowpea storage, such as quantity of seeds and type of storage container. For this purpose, we tested the efficacy of essential oils extracted from four native plants in controlling Callosobruchus maculatus, the major pest of stored cowpeas. First, we evaluated Callosobruchus maculatus mortality rate in relation with increasing amount of cowpeas. Then, experiments were conducted with essential oil in two different materials: plastic and aluminium in order to determine the weevil perforation index, the intrinsic rate of natural increase and the rate of cowpea germination. In fine, aromatized powder mixed with cowpea seeds are used against Callosobruchus maculatus by evaluating the mortality rate. The quantity of seeds influenced the efficacy of pure Lippia multiflora and Hyptis spicigera essential oils, whereas essential oils from Ocimum americanum and Hyptis suaveolens were not affected by stock size. The type of storage device used influenced the effectiveness of essential oils tested, plastic containers being more suitable than aluminium ones. Ocimum americanum used as contact insecticide in different aromatized powders exhibited variable toxic effects on C. maculatus. We conclude that essential oils appear to be safe alternatives to insecticides for long-duration storage of cowpeas
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Yield stability of legume crops is constrained by a number of pest and diseases. Major diseases are rusts, powdery and downy mildews, ascochyta blights, botrytis gray molds, anthracnoses, damping-off, root rots, collar rots, vascular wilts and white molds. Parasitic weeds, viruses, bacteria, nematodes and damages caused by chewing and sap-sucking insects add to this long list of constraints for legume production. Their incidence and relative importance together with current understanding of their interactions with the host plants are presented. State of the art of current achievements and limitations for breeding for biotic stress resistance are listed and critically discussed. The recent development of large scale phenotyping, genome sequencing and analysis of gene, protein and metabolite expressions can be of great help to further decipher plant-pathogen interactions and identify key resistance components that may be introgressed into crop plants through breeding.
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The results of bioassay indicated that per cent adult emergence, mean time of adult emergence and per cent weight loss were most important parameters which helped in categorizing the genotypes into susceptible or resistant. Out of nine interspecific progenies, one of progeny UPAS120 × C. scarabaeiodes was found least susceptible for Callosobruchus chinensis, while other progenies in the descending order for resistance to bruchid were UPAS120 × C. cajanifolius, PA134 × C. scarabaeiodes, PA134 × C. acutifolius, ICPL84023 × C. cajanifolius and ICPL84023 × C. scarabaeiodes. Since genetic resistance is the cheapest source of resistance in managing the biotic stress, the resistant material found in this study will definitely useful in the pigeonpea improvement programme especially for bruchid resistance.
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Storage insects are aerobic organisms requiring oxygen for their survival. Therefore, they respond to altered atmospheric gas compositions containing low O2 or high CO2. The lower the grain moisture content (m.c.) and the corresponding intergranular humidity, the higher the mortality—due to the desiccation effect on insects caused by low O2 or elevated CO2 concentrations. To achieve insect control, the temperature of the grain should be above 21 °C. Hermetic storage is based on the principle of generation of an oxygen-depleted, carbon dioxide-enriched interstitial atmosphere caused by the respiration of the living organisms in the ecological system of a sealed storage. A sufficiently low oxygen and elevated CO2 atmosphere is created through a natural metabolic process based on insect respiration and, in cases where the commodity has sufficiently high moisture, the respiration of the microorganisms within a sealed storage system. An O2 ingress rate of 0.05 %/day is sufficient to arrest the theoretical weight loss at a level of 0.018 % over 1-year storage period. At this ingress rate, the possibility of a residual surviving insect population is eliminated. This low O2 ingress level could serve as a guideline for the sealing specifications of structures appropriate to the hermetic storage method. The applications for which hermetic technology has been most widely accepted are (a) for long-term storage of cereal grains, primarily rice, corn, barley, and wheat; (b) for long-term storage of a variety of seeds to preserve germination potential and vigor, and (c) for quality preservation of high-value commodities, such as dried fruits.
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Infestations of stored legume seeds by bruchid beetles, such as the cowpea weevil and the Azuki bean weevil cause substantial economic and nutritional losses of these food crops, especially in developing countries. Seeds of the common bean are resistant to these bruchids largely because of the presence of -amylase inhibitor (AI-Pv), a seed protein that is toxic to the larvae. The AI-Pv gene is therefore a candidate for a genetic engineering approach that would make other legumes (pea, chickpea, cowpea, Azuki bean) resistant to bruchid infestations. We tested this possibility by transforming peas (Pisum sativum) with the AI-Pv gene driven by a strong seed-specific promoter. The levels of AI protein in the pea seeds were as high as in bean seeds and the peas were resistant to the cowpea and Azuki bean weevils.
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Bruchid larvae cause major losses of grain legume crops through- out the world. Some bruchid species, such as the cowpea weevil and the azuki bean weevil, are pests that damage stored seeds. Others, such as the pea weevil (Bruchus pisorum), attack the crop growing in the field. We transferred the cDNA encoding the a-amylase inhibitor (a-AI) found in the seeds of the common bean (Phaseolus vulgaris) into pea (Pisum sativum) using Agrobacferium-mediated transformation. Expression was driven by the promoter of phytohe- magglutinin, another bean seed protein. The a-amylase inhibitor gene was stably expressed in the transgenic pea seeds at least to the T, seed generation, and a-AI accumulated in the seeds up to 3% of soluble protein. This level is somewhat higher than that normally found in beans, which contain 1 to 2% a-AI. In the 1, seed generation the development of pea weevil larvae was blocked at an early stage. Seed damage was minimal and seed yield was not significantly reduced in the transgenic plants. These results confirm the feasibility of protecting other grain legumes such as lentils, mungbean, groundnuts, and chickpeas against a variety of bruchids using the same approach. Although a-AI also inhibits human a-amy- lase, cooked peas should not have a negative impact on human energy metabolism.
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Weevils can devastate food legumes in developing countries, but genetically modified peas (Pisum sativum), chickpeas and cowpeas expressing the gene for alpha-amylase inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are completely protected from weevil destruction. αAI is seed-specific, accumulated at high levels and undergoes post-translational modification as it traverses the seed endomembrane system. This modification was thought to be responsible for the reported allergenicity in mice of the transgenic pea but not the bean. Here, we observed that transgenic αAI peas, chickpeas and cowpeas as well as non-transgenic beans were all allergenic in BALB/c mice. Even consuming non-transgenic peas lacking αAI led to an anti-αAI response due to a cross-reactive response to pea lectin. Our data demonstrate that αAI transgenic peas are not more allergenic than beans or non-transgenic peas in mice. This study illustrates the importance of repeat experiments in independent laboratories and the potential for unexpected cross-reactive allergic responses upon consumption of plant products in mice.
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Recognizing that it takes Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) larvae over 24 h to bore into a dry red kidney bean {Phaseolus vulgaris L.) and that boring can occur only at particular sites where a bean abuts some other surface, we postulated that this pest might be controlled by periodic tumbling of beans so as to place initiated holes out of register with requisite touching surfaces. Larvae repeatedly forced to initiate holes might die of exhaustion, if not smashed by tumbling beans. Indeed, brief daily tumbling of beans held in half-filled jars, buckets, and gunny sacks reduced A. obtectus populations by 97% relative to stationary controls. We recommend that small lots of beans can be protected indefinitely from the bean weevil when stored in <75% filled cylinders rolled ca 1 circumference every morning and evening. This control method should be immediately useful, particularly among subsistence families, since the only external input is knowledge. Also, this control principle might be broadly applicable to other bean and grain pests having strict spatial and temporal requirements for seed penetration.
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Storage insect pests cause significant losses of food legumes particularly in the Tropics and the Sub-tropics. The most important species of storage insect pests of food legumes include Callosobruchus chinensis , C. maculatus , C. analis , Acanthoscelides obtectus , Bruchus incarnatus , B. rufimanus , B. dentipes , B. quinqueguttatus , B. emarginatus , B. ervi , B. lentis and B. pisorum . Effective post-harvest insect pest control measures should constitute part of the overall crop husbandry practices for preserving the quality of produce. Storage insect pests are commonly controlled using chemical insecticides which, however, bear many drawbacks related to high cost, environmental pollution and food safety risks. Breeding legume crops to improve their resistance against storage insect pests, although having technical limitations, is the best way of overcoming these disadvantages in an environment-friendly manner. In this paper, we present the findings of our extensive reviews on the potential of breeding resistant varieties of food legumes against storage insect pests along with the major technical limitations one would likely encounter and the prospective ways of tackling them.
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We describe a robust and reproducible Agrobacterium-mediated chickpea transformation method based on kanamycin selection, and its use to introduce the bean AI1 gene into a desi type of chickpea. Bean AI1 was specifically expressed in the seeds, accumulated up to 4.2% of seed protein and was processed to low molecular weight polypeptides as occurs in bean seeds. The transgenic protein was active as an inhibitor of porcine -amylase in vitro. Transgenic chickpeas containing -AI1 strongly inhibited the development of Callosobruchus maculatus and C. chinensis (Col. : Bruchidae) in insect bioassays.
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Continuing population and consumption growth will mean that the global demand for food will increase for at least another 40 years. Growing competition for land, water, and energy, in addition to the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement to reduce the impact of the food system on the environment. The effects of climate change are a further threat. But the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.
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The cowpea is a very important legume for peasant farmers in West Africa but this crop is very sensitive to bruchid attacks during storage. A study was carried out in a sub humid zone of Burkina Faso to determine the relation between the dynamic of bruchid and parasitoid populations in the fields and cowpea infestation at harvest. The variations in insect numbers were weekly estimated by net captures during the growth of an early and a late cowpea variety. Adults of two bruchid species, Callosobruchus maculatus (Fab.). and Bruchidius atrolineatus (Pic) appeared early in the fields before cowpea flowering and their population regularly increased over time and from early to late cowpea variety. The Pteromalid Dinarmus basalis Rond was the only larval parasitoid encountered. Its adults appeared later than bruchids and their parasitism activity increased over time. At harvest, 35% of the early cowpea pods and 74.5% of the late cowpea pods were infested by bruchid eggs. 58.5 and 72% of the bruchid eggs laid respectively on the early and the late cowpea variety were parasitized by Uscana sp. The level of cowpea seed infestation by bruchids at the beginning of storage was estimated to be 1 and 2.7% for the early and late cowpea variety respectively. The parasitism rate of bruchid larvae by D. basalis was estimated at this period to be 7.8% for early cowpea variety and 18.2% for the late variety. These results are discussed in view of developing an integrated control method based on the enhancement of the pest natural enemies in the fields and/or into storage systems in combination with beneficial farming practices.
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Food storage is a vital component in the economic and social package that comprises the Neolithic, contributing to plant domestication, increasingly sedentary lifestyles, and new social organizations. Recent excavations at Dhra' near the Dead Sea in Jordan provide strong evidence for sophisticated, purpose-built granaries in a predomestication context approximately 11,300-11,175 cal B.P., which support recent arguments for the deliberate cultivation of wild cereals at this time. Designed with suspended floors for air circulation and protection from rodents, they are located between residential structures that contain plant-processing instillations. The granaries represent a critical evolutionary shift in the relationship between people and plant foods, which precedes the emergence of domestication and large-scale sedentary communities by at least 1,000 years.
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Cowpea is one of the important grain legumes. Storage pests, Callosobruchus maculatus and C. chinensis cause severe damage to the cowpea seeds during storage. We employ a highly efficient Agrobacterium-mediated cowpea transformation method for introduction of the bean (Phaseolus vulgaris) alpha-amylase inhibitor-1 (alphaAI-1) gene into a commercially important Indian cowpea cultivar, Pusa Komal and generated fertile transgenic plants. The use of constitutive expression of additional vir genes in resident pSB1 vector in Agrobacterium strain LBA4404, thiol compounds during cocultivation and a geneticin based selection system resulted in twofold increase in stable transformation frequency. Expression of alphaAI-1 gene under bean phytohemagglutinin promoter results in accumulation of alphaAI-1 in transgenic seeds. The transgenic protein was active as an inhibitor of porcine alpha-amylase in vitro. Transgenic cowpeas expressing alphaAI-1 strongly inhibited the development of C. maculatus and C. chinensis in insect bioassays.
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RNA interference induced in insects after ingestion of plant-expressed hairpin RNA offers promise for managing devastating crop pests.
Article
The cowpea weevil, Callosobruchus maculatus (F.), is a major pest of cowpea Vigna unguiculata (L.) Walp. in storage units, making the grains unsuitable for consumption. The adverse effects of chemical control methods have been motivating the demand for alternatives in pest control, such as the use of natural products like essential oils. The aim of this study was to obtain and chemically identify the components of essential oils extracted from fruit peels of Citrus latifolia Tanaka, Citrus reticulata Blanco, Citrus sinensis L. Osbeck and Citrus paradisi Macf., as well as to determine the contact and fumigant toxicity of these oils and their repellent effect on C. maculatus adults. The GC-MS analysis identified 45 compounds in the essential oils; the major components were described as follows: C. latifolia (limonene 57.7%, γ-terpinene 17.2%, β-pinene 12.3%, α-pinene 2.0%), and C. sinensis (limonene 93.8%, myrcene 2.1%), C. reticulata (limonene 94.2%, myrcene 1.6%) and C. paradisi (limonene 94.2%, myrcene 1.8%). In the contact toxicity tests using treated cowpeas the LC50 values ranged from 943.9 to 1037.7 ppm, with the lowest value for C. latifolia and the highest for C. sinensis. The number of eggs and newly emerged adults was inversely proportional to essential oil concentration increase. In the fumigant toxicity test, LC50 values ranged from 10.2 to 12.98 μL/L air, with C. latifolia showing the best results. In the repellency test, the essential oils were classified as neutral at all concentrations. The percentages of oviposition reduction ranged from 29.74 to 71.66%, while reduction in emergence varied from 15.43 to 85.31%. Essential oils of citrus peels (industrial waste) could be widely used for C. maculatus control. Moreover, they could gain economic value if used on a large scale to produce essential oils.
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
Fumigated dry common beans (Phaseolus vulgaris L.) that were artificially infested with Acanthoscelides obtectus Say, and others that were not artificially infested, were stored in hermetic triple-layer PICS (Lela Agro, Kano, Nigeria) or woven polypropylene (PP) bags for 6 mo at ambient laboratory temperature conditions of 22.661.9_C and 60.164.3% relative humidity. In an additional trial, beans contained in PP bags were treated with Actellic Super dust before introducing A. obtectus. Moisture content, number of live adult A. obtectus, seed damage, weight loss, and seed germination were determined at monthly intervals. At 6 mo, beans stored in PICS bags retained higher moisture than those stored in PP bags, but in all treatments the moisture level remained below that recommended for safe storage of beans. In the PICS bags, proliferation of A. obtectus did not proceed and at 6 mo, beans stored in these bags did not have insect-inflicted seed damage or weight loss. In contrast, seed damage and weight loss in PP bags exceeded economic threshold after 1 mo in the absence of Actellic Super dust (Syngenta Crop protection AG, Basle, Switzerland), and after 2mo in the presence of it. Germination of beans stored in PP bags decreased greatly whereas the beans stored in PICS bags did not show reduced germination. Chemical free storage of common beans in PICS bags protects them against damage by A. obtectus.
Article
Cereals and pulses have great biological and nutritional value in human diet. The losses during growing crops and post harvest handling, processing, storage and distributions systems vary between 20-60%. Three major groups of storage enemies are: fungi, insects and rodents. Many insecticides are available that can be used for protection of stored cereals and pulses. The growing awareness of environment as well as health hazards from synthetic pesticides leads to alternate method. Researchers and users are trying organic pesticides/ biopesticides for this grain storage purpose. Out of these products, oils from plant origin are one of them, which have been found to possess insecticidal properties. An advantage is that they are easy to apply. There are also some disadvantages to the use of oil: Oil can have an adverse effect on the germination power of the oil treated seeds.
Almost every site excavated from Iron Age Palestine contains numerous pits. This article proposes that those ancient pits may have served as grain storage receptacles. It begins by demonstrating that the use of pits as granaries has much historical precedence in Rome, Greece, and Africa. Then it looks at the biblical evidence that confirms the thesis. In examining the archaeological evidence from Palestine the article discusses pitting at several major excavated sites. Finally, it reports on the Lahav Grain Storage Project. The primary purpose of that project was to determine if the subterranean pit, designed and constructed like Iron Age pits, would operate properly and adequately for grain storage. Project participants built and tested four replicas of Iron Age pits for grain storage. The experiments showed that subterranean pits do provide an excellent place to store grain. Such facilities were used widely in the Iron Age.
Article
Experiments were conducted to evaluate the performance of hermetic triple bagging using Purdue Improved Crop Storage (PICS) bags for storage of Bambara groundnut (Vigna subterranea (L.) Verdc.). One set of experiments used grain heavily infested by Callosobruchus maculatus (F.) while a second set began with a low level infestation. Each experiment consisted of V. subterranea grain kept in four replicate 50 kg PICS bags or two replicate woven bags as controls. Two to five days after the beginning of the experiments, oxygen level inside the bags averaged about 21% (v/v) in the controls but decreased significantly in PICS bags, reaching 10% (v/v) with the heavily infested grain but falling only slightly in the lightly infested grain. After 7 months of storage, (i) the number of C. maculatus adults found between and within the grains, (ii) the 100 seed weight, (iii) the number of seed with holes, and (iv) the percentage germination of grain stored in PICS bags did not differ from what had been measured on the day that the experiment was set up. In woven bags, by contrast, there was a massive increase in C. maculatus numbers with means of 309 and 251 adults per 500 g in heavily and lightly infested grain, respectively. Grain weight losses in the woven bag controls ranged from 8 to 19% and the percentage of C. maculatus emergence holes per 100 seed increased from 51 to 135%.
Article
When cowpea bruchid-infested cowpea grain was stored for four-plus months in Purdue Improved Cowpea Storage (PICS_) bags or in commercially-available GrainPro SuperGrain_ bags, preservation of the grain was equally good in both types of bags. In both bag types oxygen (O2) levels dropped rapidly during the first 24 h after closure, eventually reaching levels of 1e3 percent by volume (v/v). With both types of bag there was an initial rise in temperature during the first 24 h, followed by a decline, in time reaching ambient. Over the four-plus months of the experiment damage levels did not significantly increase in either type of bag while control grain kept in a conventional woven plastic bag suffered severe damage. Most of the insects found in both GrainPro and PICS bags at the end of the experiment were dead. The single layer SuperGrain_ bags showed more bruchid holes than did triple-layer PICS bags, which had no holes penetrating through both of the inner high density polyethylene (HDPE) layers, meaning that an intact O2 barrier remained in place even after the inner HDPE layer was holed. Farmers who wish to store their cowpea grain with either technology can choose between the two types of bags, taking into account price, availability and durability.
Article
The Gram-positive bacterium Bacillus thuringiensis produces proteins which are specifically toxic to a variety of insect species. Modified genes have been derived from bt2, a toxin gene cloned from one Bacillus strain. Transgenic tobacco plants expressing these genes synthesize insecticidal proteins which protect them from feeding damage by larvae of the tobacco hornworm.
Article
Vegetable oil at a dosage of 1ml/kg bean seed, Phaseolus vulgaris (L.), showed insecticidal effectiveness against Zabrotes subfasciatus (Boheman) infesting stored beans. The active oil fraction appeared to be the triglyceride component. Oleic acid appeared to be the only effective fatty acid of the ones tested. Linolenic and arachidonic acid showed some insecticidal effect.
Article
Vegetable oils at the rate of 1 ml/kg of bean seed, Phaseolus vulgaris L., provided a high level of control against attack of a bruchid Zabrotes subfasciatus (Boheman). At 5 or 10 ml/kg bean seed, complete control was achieved and lasted over 75 days for some oils. Crude oils provided significantly better protection than purified oils, and the level of control of the different oils varied significantly. The oils increased adult mortality and reduced oviposition, egg hatching, and number of adult progeny. Oil treatment of larval-infested beans at 5 ml/kg significantly reduced progeny adult emergence. Manual application of oils provided significantly less control than tumbler application at 1 ml/kg. Both oil treated and nontreated beans germinated equally well. Water absorption of oil-treated and untreated beans soaked for 24 h was the same, independent of length of storage after oil application. Oil applications are cheap (0.5% of market price of beans in Colombia) , safe, and easy to do.
Article
Seeds of cowpea, Vigna unguiculata (L.) Walp, line `TVu 2027' are moderately resistant to the cowpea weevil, Callosobruchus maculatus (F.). C. maculatus larvae exhibit higher mortality and take longer to develop in `TVu 2027' than in more susceptible seeds. Claims have been made (Gatehouse, A.M.R., J. A. Gatehouse, P. Dobie, A. M. Kilminster & D. Boulter. 1979. Biochemical basis of insect resistance in Vigna unguiculata. J. Sci. Food Agric. 30: 948-958) that an elevated level of cowpea trypsin inhibitor (CPTI) confers resistance to `TVu 2027'. To test this hypothesis, we isolated and purified CPTI and evaluated its impact on cowpea weevil using an artificial seed system. CPTI at dietary levels up to 2.0% (wt/wt) caused no significant increase in mortality of cowpea weevils and only slight delays in within-seed developmental times. These results do not support the hypothesis that CPTI is the basis of resistance in `TVu 2027'.
Article
Callosobruchus maculatus (F.) is a very serious pest of cow pea in storage in Nigeria and many other oountries (Singh, 1977; Tindall, 1983). Damaged seeds are riddled with emergence holes, defaced with egg covers and have reduced viability. Heavy attack causes severe powdering and weight loss. In Nigeria, about 30–60% loss in cow pea is attributed to infestation and damage by bruchid beetles over a 3- to 6-month storage period, of which over 90% is caused by C. maculatus alone (Caswell, 1981).(Received April 12 1986)(Revised April 12 1986)
Article
The bruchid beetle Callosobruchus maculatus (F.) causes extensive damage to seeds of the cowpea, Vigna unguiculata (L.) (Walp.), when this important tropical foodstuff is stored. A variety of cowpea resistant to attack by this pest has been described. In the present work seeds of a number of cowpea varieties, including the resistant one, were tested for the presence of a physical resistance to C. maculatus, in terms of repulsion of oviposition or of failure of larvae to enter the seeds. No evidence to suggest the presence of a physical resistance was found. When seeds of cowpea varieties were tested for the presence of various antimetabolic secondary compounds, only inhibitory activity against trypsin and, to a much lesser extent, chymotrypsin, could be detected. The resistant variety of cowpea contained a significantly higher level of inhibitors, about twice as much as any other variety. A proteinase inhibitor active against trypsin was purified from cowpea varieties by affinity chromatography on trypsin-Sepharose. The purified inhibitor was shown to inhibit chyraotrypsin also, in such proportions as to account for chymotrypsin inhibition by seed extracts. The inhibitor was shown to consist of a number of isoinhibitors by gel electrophoresis and isoelectric focusing, but no qualitative differences in the inhibitor between varieties could be detected. The antimetabolic nature of the cowpea trypsin inhibitor was confirmed by insect feeding trials in which various protein fractions were added to a basic meal and the effect on larval survival noted. The albumin proteins of cowpea (containing the trypsin inhibitors) at a level of 10% were toxic to larvae of C. maculatus whereas the globulin fractions were not. Further, if cowpea trypsin inhibitor was removed from the albumin proteins they ceased to be toxic. When purified cowpea trypsin inhibitor was added to the basic meal it was shown that a level slightly less than that found in the resistant variety of cowpea caused complete mortality of larvae, whereas lower levels had lesser or no effect. It is concluded that this example of insect resistance in the cowpea is due to an elevated level of trypsin inhibitor.
Article
Much of the proteolytic activity in the digestive tract of Callosobruchus maculatus larvae can be attributed to a thiol proteinase(s) that hydrolyzes [3H]methemoglobin optimally at pH 5.0. Maximal hydrolysis of [3H]methemoglobin, [3H]alpha-casein, and N-benzoyl-DL-arginine napthylamide-(BANA) required the presence of thiol reducing agents. Larval gut proteinase activity was strongly inhibited by p-hydroxymercuribenzoic acid (pHMB), Nethylmaleimide (NEM), and iodoacetic acid (IAA) but was unaffected by the Bowman-Birk and Kunitz proteinase inhibitors from soybeans or by lima bean trypsin inhibitor. L-Trans-epoxysuccinyl-leucylamido-(4-guanidino)-butane (E-64), a specific inhibitor of thiol proteinases, potently inhibited proteolysis of [3H]methemoglobin by larval gut homogenates. Proteolytic activity in the larval gut was located in the lumen contents and thus appears to play a major role in extracellular digestion. The pH of the larval midgut is slightly acidic, and midgut contents exhibit a negative redox potential, conditions supporting the activity of a thiol proteinase. The significance of these findings is discussed with reference to the vulnerability of this digestive proteinase as a target for existing or genetically engineered plant chemical defenses.
Article
Data on 228 accessions of eight annual wild Cicer species and 20 cultivated chickpea check lines were evaluated for diversity in response to six of the most serious biotic and abiotic stresses which reduce crop yield and production stability of chickpea, i.e., ascochyta blight, fusarium wilt, leaf miner, bruchid, cyst nematode, and cold. Relative frequencies of score reactions to the above six stresses were recorded from all the annual wild Cicer species and the cultivated taxon. Patterns of distribution and amount of variation of the resistance reactions differed between stresses and species. C. bijugum, C. pinnatifidum and C. echinospermum showed accessions with at least one source of resistance (1 to 4 score reactions) to each stress. Overall, C. bijugum showed the highest frequencies of the highest categories of resistance. Next in performance was C. pinnatifidum followed by C. judaicum, C. reticulatum and C. echinospermum. Furthermore, C. bijugum had the highest number of accessions with multiple resistance to the six stresses; two accessions were resistant to five stresses and 16 to four. According to the Shannon-Weaver diversity indices (H), five species showed discrete mean diversity indices which varied from 0.649 in C. pinnatifidum to 0.526 in C. judaicum, whereas C. chorassanicum, C. cuneatum and C. yamashitae showed the lowest Hs, which were respectively 0.119, 0.174 and 0.216. Pair-wise correlations among the six biotic and abiotic stresses showed the possibility of combining these resistances. Interestingly, multiple resistant accessions were predominantly of Turkish origin.
Article
Consumer demand for more natural, minimally processed and fresh foods is increasing. Modified atmosphere storage is a well-proven technology for preserving natural quality of food products in addition to extending the storage life. Extensive research has been done in this research area around the globe for many decades. Modified atmosphere storage is one of the most successful preservation techniques suitable for wide varieties of agricultural and food products. Grain farmers are seeing advantage in using this method as strict regulations are enforced on the use of other chemical preservation methods. Success of modified atmosphere storage of grains depends on the airtightness of the grain bins and research is needed to find the techniques to improve the sealability of the existing grain bins. It is widely practiced in the meat industry for preserving primal and sub-primal cuts. Modified atmosphere packaging is also commercially successful for preserving certain fruits and vegetables. With the vast basic and fundamental knowledge available on this subject, the research in this area is taking a new dimension to suit the new consumer trends and demands. There are new interests in applying this technique to the consumer-ready products in the meat industry. This technique can be integrated with active or interactive packaging to improve the control over the package atmosphere to achieve superior product quality and safety. Time–temperature indicators on the packages to show the remaining storage life of the food product would improve food safety and inventory control. In this paper, published research on modified atmosphere storage specifically on grains, meats, fruits and vegetables is critically reviewed and opportunities for future research are explored.
Article
Several technologies reputedly minimize losses of stored cowpea grain to bruchid beetles on low resource farms in Africa. Side by side comparison of these different postharvest storage methods can provide the basis for deciding which performs best. We compared six different technologies for cowpea storage: (1) grain mixed with ash; (2) mixed with sand; (3) fumigated with phostoxin; (4) admixed with the stems and leaves of Boscia senegalensis (Pers) Lam ex Poir, a potential botanical insecticide; (5) disinfested using a solar heater, and; (6) hermetically sealed in triple-layer plastic bags. Sampling was done at thirty-day intervals over five months of storage. Counts were made of (i) adult emergence holes, (ii) dead larvae and (iii) surviving bruchid larvae and adults. Controls, which consisted of infested cowpea grain stored in cloth bags, were damaged extensively. Bosciasenegalensis-treated grain suffered similar severe damage. All other treatments suppressed bruchid population increases as was evident from the much lower counts of emergence holes and lower numbers of surviving or dead insects.
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.