Mung bean is highly susceptible to insect attack during storage. Hermetic storage is an effective technique to control insect damage. This study investigated the potential of the hermetic SuperGrain bag (SGB) for controlling bruchids during storage. The dry samples were packed in SGB infested with adult bruchids (SGB-I), SGB natural field infested (SGB-N), woven polypropylene bags (WPP-I and WPP-N) and kept at room temperature for 180 days. Oxygen (O2) and carbon dioxide (CO2) concentrations were measured at 15 days intervals. Moisture content, infestation level, seed damage and weight loss were determined at 60 days intervals. Seed colour, hardness, crude protein and fat contents were analysed before and after storage. The O2 level decreased to 10.09%, whereas the CO2 level increased to 8.87% in both SGB-I and SGB-N treatments. The moisture content of mung bean was maintained as onset storage in both SGB-N and SGB-I treatments, whereas reduced in WPP-N (9.26% db) and WPP-I (9.21% db). In SGB treatments, no significant bruchids were detected, but they increased drastically in WPP-N (52 ± 9) and WPP-I (377 ± 14). Seed damage (2–3%) and weight loss (0.8–1.0%) were recorded in both SGB-N and SGB-I. Conversely, seed damage reached 26.67 and 54.17%, corresponding to weight losses of 12.33 and 20.82% in WPP-N and WPP-I, respectively. Seed colour, hardness, crude protein and fat contents in SGBs showed no significant changes than in the WPP bags. The study illustrated that the SGB is an efficient hermetic device in protecting mung beans against bruchids attacks compared to the WPP bags.

Seeds of the common bean, Phaseolus vulgaris, contain two inhibitors of mammalian and insect α-amylases (αAls) that show specificity towards the amylases of different insect species. Expression in pea (Pisum sativum) and azuki bean (Vigna angularis) of a chimeric gene consisting of the cDNA of bean αAl-1 and a seed-specific promoter makes the seeds of these legumes resistant to three species of Old World bruchids whose amylases are inhibited by αAl-1. This was the first successful genetic engineering of insect resistance in seeds. To understand the basis of the specificity between amylases and inhibitors we cloned a second bean inhibitor (αAl-2) with different specificity, and we cloned the cDNA of the New World bruchid, Zabrotes subfasciatus. The amylase of this bruchid is inhibited by αAl-2, but not by αAl-1. Knowledge of the amino acid sequences and of the three-dimensional structure of the pancreatic α-amylase–αAl-1 complex allows us to predict the peptide domains and amino acids of the proteins that are important for protein–protein recognition and inhibition of enzyme activity.

Mungbean seeds are often attacked by bruchid insects causing serious damage to the grain during storage. The susceptible/resistant characteristics of mungbean against bruchids have been investigated at the protein level. Seeds of the susceptible cultivar Osaka-ryokuto and the resistant near-isogenic line BC20 were collected at 5, 9, 13, 17, 21 and 23 days after flowering. Crude, cytosol and membrane protein fractions were extracted from the seeds for twodimensional polyacrylamide gel electrophoresis analysis. In Osaka-ryokuto six proteins were found in higher amounts compared to BC20 in the crude protein extract. Some of these proteins were homologous to legumin B and liguleless1. And in BC20 one unique protein, homologous to SalF1R, was identified. In the subcellular protein fractions, nine unique proteins were identified in BC20, seven in the cytosol and two in the membrane fractions. These proteins were homologous to chitinase, alanine aminotransferase in membrane, and SalF1R, β-1,3- glucanase, protein phosphatase 2A, peroxidase BP 2A, provicilin and canavalin in the cytosol fractions. Previous findings of many researchers reveal that these are mainly defence-related proteins. Thus, it is suggested that the above proteins may play a role in maintaining the resistance of line BC20.

This study was conducted to identify the individual biochemical factors involved in the resistance observed in a few Mexican bean accessions against the bean weevil, Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae). Soluble proteins from different bean genotypes were separated by fractionated acetone precipitation. Insects were reared on artifical seeds composed of a susceptible background bean flour enriched with the different protein fractions. At low doses (2% w/w), the 0–20% and 20–40% acetone fractions of the resistant bean accessions G 12954 and G 12880 inhibited larval growth of the bean weevil, but not of a related species, the Mexican bean weevil, Zabrotes subfasciatus (Boheman). The 0–20% fraction caused the highest mortality of first instar larvae. The 60–80% acetone fraction contains general resistance factors, like α-amylase and protease inhibitors, which when enriched in artifical seeds led to a strong depression of insect growth for resistant and susceptible bean accessions alike. These factors should also be taken into account in breeding for multigenic, durable resistance, in order to exploit the synergism between general and specific resistance factors.

Bruchidius atrolineatus Pic is a Coleopteran Bruchid developing in cowpea (Vigna unguiculata Leguminosae) seeds. This insect causes important damage in tropical countries during storage of cowpea seeds. The influence of some volatile sulfur compounds is studied on adults and larvae of B. atrolineatus. Dimethyl trisulfide and diethyl trisulfide produce the highest mortality to adults, eggs and larvae. The toxicity of the sulfur compounds is higher than that of carbon tetrachloride but is less than that of Dichlorvos at a dosage of 500 g/l. It is suggested that the sulfur compounds produced by the leaves of some tropical plants (Alliaceae, Bignonlaceae, Mimosaceae) could be used for control of Bruchid populations in the stored products.

In the tropics, insect pests cause considerable damage to soybean, Glycine max and mungbean, Vigna radiata from germination until harvest and even in storage. Agromyzid flies in the seedling stage, lepidopterous and coleopterous defoliators in the vegetative and early reproductive stages, pentatomid and coreid bugs and lepidopterous pod-borers in the reproductive stage, and bruchids in storage all cause significant damage. Sources of resistance to agromyzids in mungbean (AVRDC accession V 4281), defoliators (PI 171451, PI 227687, PI 229358) and stink bugs (PI 227687 and PI 171444) in soybean, and bruchids in mungbean (V 2164) are available. In most cases, antibiosis appears to be the major mechanism of resistance. These sources are being exploited in the development of agromyzid-resistant mungbean, defoliator- and stink bug-resistant soybean, and bruchid-resistant mungbean at the Asian Vegetable Research and Development Center (AVRDC). Diversity in insect species within a pest complex and, in certain cases, biotypes of single pest at different locations as well as pest ecology are likely to influence the resistance reaction and, in practical terms, the utilization of pest resistance as a tool in the management of insect pests of soybean and mungbean. Greater efforts are required at local level to fully utilize insect pest resistant germplasm.

Cowpea is one of the most widely grown leguminous crops in Africa: in Kenya it occupies over 66,000 ha and Coast Province ranks second to Eastern Province with about 5200 ha. It is an important food item consumed both as a vegetable and as a grain. Unfortunately, it suffers from both preharvest and postharvest infestations which accounts for serious losses of the crop. With the introduction to Kenya of improved varieties from IITA, Nigeria, such losses would be increased due to varying susceptibility in different pest ecosystems. The objective of this study therefore was to observe the infestation of the IITA varieties and compare them with local cowpea varieties collected from different parts of Kenya. The work was conducted at C.A.R.S., Mtwapa from 1979 to 1981 inclusive. From the study, five different bruchid species were identified as infesting cowpea varieties in the field. These were Collosobruchus rhodensienus; C. phaseoli; C. chinensis; Bruchidius atrolineatus; and C. analis; in order of decreasing abundance. Over 50% of the bruchids found in the field were C. rhodensienus while Zabrotes spp. and C. maculatus (F) were never encountered in the field. Although the IITA materials were introduced because of their yield potential, it was found that some of them were as susceptible to preharvest bruchid attack as the locally available materials. The short rains season had more bruchid infestations than the long rain season. There were also fewer eggs on pods of local varieties and fewer bruchids emerging from seeds of local as compared to IITA varieties. The results however were not significantly different. Further work should be done to establish the complex of bruchids found in stored cowpea varieties, the losses caused and control measures applicable to reduce damage.

Decrease in trehalose (40–60%) and total sugar (58–68%) content was observed in both sexes of ageing Callosobruchus maculatus. The variations in the level of trehalose and total sugar with age, suggest that these serve as energy sources responsible for the maintenance of metabolism in the process of ageing in bruchids.