Cowpea Bruchid Callosobruchus Maculatus Research Articles

Efficacy of Two-In-One Model Traps and Sun Drying against Callosobruchus Maculatus (F.) in Mungbean

Detection of insect infestations is essential for quality assurance and helps in locating insect infestations, for early diagnosis of low-level infestation and to ascertain the success of control measures. This study evaluates the efficacy of two-in-one model trap against cowpea bruchid Callosobruchus maculatus (F.) in stored mungbean in six months of storage. Tamil Nadu Agricultural University (TNAU) developed two-in-one model traps were used. The observations on number of adult beetles trapped, % weight loss and grain damage were recorded at the end of each month, for six months. The results obtained conclude that use of one trap and sun drying of mungbean grains for five days is significantly effective in reducing the number of adult beetles. No weight loss and grain damage were recorded with this treatment, where only one trap/ container was used followed by sun drying for five days at the end of fourth month. Similar results were obtained up to six months. The % weight loss of 1.75 and 4.00% grain damage observed at the end of sixth month with one trap and three day sun drying of grains exhibit its efficacy.

Use of Microwave Heating Technology for Disinfestation of Stored Green Gram (Vigna radiata) against Cowpea Bruchid Callosobruchus maculatus (Fabricius)

Background: Pulses are an integral component of food in India which acts as major source of protein required for growth and maintenance of body. But during their storage they suffer heavy losses resulting in depletion of their quality and edibility. The present studies focused on disinfestation of green gram grains using microwaves as an alternative approach to chemical methods for controlling insects in grains and pulses. Methods: In this laboratory studies during 2017-18, the grains of green gram were infested with different life stages of the cowpea weevil and exposed to 200, 400, 600 and 800 W microwave power levels, each at an exposure period of 10, 20, 30 and 40 s. Result: Eggs were the most susceptible, while pupal and adults were the least susceptible life stages to microwave treatments. Complete mortality of eggs was achieved with microwave treatments (400, 600 and 800 W), each at an exposure period of 30 and 40 s. Complete inhibition of larval stage was attained with 400 and 600 W (30 and 40 s) and 800 W (20, 30 and 40 s exposure) while for pupal stage it was observed at the higher wattages of 600 (40 s exposure) and 800 (30 and 40 s exposure). Microwave wattage of 600 W for 40 sand 800 W for 30 and 40 s exposure caused 100% mortality of 2d old adults of cowpea bruchid.

English

Quantification of total Phenolic and Flavonoid Contents, and GC-MS Profile of Extracts of Piper Guineense, Dennettia Tripetala and Ocimum Gratissimum used in the Control of Cowpea Bruchid Callosobruchus Maculatus in Storage Grains

Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus.

Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology.

Storage of mung bean (Vigna radiata [L.] Wilczek) and pigeonpea grains (Cajanus cajan [L.] Millsp) in hermetic triple-layer bags stops losses caused by Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Dry mung bean and pigeonpea grains that had sustained some insect damage but fumigated before the start of the experiment were stored in triple-layer hermetic bags (Purdue Improved Crop Storage (PICS™ bags) or woven polypropylene (PP) bags for 6 months. Some of the bags were artificially infested with cowpea bruchid Callosobruchus maculatus (F.) (PICS1, PP1) while others were not (PICS0, PP0). In an additional trial, PP bags containing the grains were treated with Actellic Super® dust before being artificially infested (PP1Ac). Moisture content, live adult C. maculatus count, grain damage, weight loss, and seed germination were determined on a monthly basis. At six months, moisture contents of grain stored in PICS and PP bags remained below 12%. Storage in PICS bags halted multiplication of C. maculatus, and the initial damage level and weight of grains did not change. Conversely, in the PP bags, C. maculatus populations increased massively and seed damage reached 71.8 ± 1.9%, 76.9 ± 0.4%, and 60.3 ± 0.6% corresponding to weight losses of 14.5 ± 0.1%, 16.5 ± 0.2% and 12.5 ± 0.1% in PP0, PP1 and PP1Ac, respectively, in mung beans. With the pigeonpeas, seed damage reached 55.1 ± 0.6%, 95.7 ± 0.4% and 75.8 ± 0.9%, corresponding to weight losses of 13.0% ± 0.3%, 26.2 ± 0.2% and 13.5 ± 0.1%, in PP0, PP1 and PP1Ac, respectively. PICS bags are an effective tool for preserving mung beans and pigeonpeas against C. maculatus attack, and their performance is superior to that of Actellic Super® dust.

Odour-Mediated Orientation of Beetles Is Influenced by Age, Sex and Morph

The behaviour of insects is dictated by a combination of factors and may vary considerably between individuals, but small insects are often considered en masse and thus these differences can be overlooked. For example, the cowpea bruchid Callosobruchus maculatus F. exists naturally in two adult forms: the active (flight) form for dispersal, and the inactive (flightless), more fecund but shorter-lived form. Given that these morphs show dissimilar biology, it is possible that they differ in odour-mediated orientation and yet studies of this species frequently neglect to distinguish morph type, or are carried out only on the inactive morph. Along with sex and age of individual, adult morph could be an important variable determining the biology of this and similar species, informing studies on evolution, ecology and pest management. We used an olfactometer with motion-tracking to investigate whether the olfactory behaviour and orientation of C. maculatus towards infested and uninfested cowpeas and a plant-derived repellent compound, methyl salicylate, differed between morphs or sexes. We found significant differences between the behaviour of male and female beetles and beetles of different ages, as well as interactive effects of sex, morph and age, in response to both host and repellent odours. This study demonstrates that behavioural experiments on insects should control for sex and age, while also considering differences between adult morphs where present in insect species. This finding has broad implications for fundamental entomological research, particularly when exploring the relationships between physiology, behaviour and evolutionary biology, and the application of crop protection strategies.

Functional mechanics of the plant defensive Griffonia simplicifolia lectin II: resistance to proteolysis is independent of glycoconjugate binding in the insect gut.

Griffonia simplicifolia lectin II (GSII) is a plant defensive protein that significantly delays development of the cowpea bruchid Callosobruchus maculatus (F.). Previous structure/function analysis by site-directed mutagenesis indicated that carbohydrate binding and resistance to insect gut proteolysis are required for the anti-insect activity of this lectin. However, whether there is a causal link between carbohydrate binding and resistance to insect metabolism remains unknown. Two proteases principally responsible for digestive proteolysis in third and fourth instar larvae of C. maculatus were purified by activated thiol sepharose chromatography and resolved as cathepsin L-like proteases, based on N-terminal amino acid sequence analysis. Digestion of bacterially expressed recombinant GSII (rGSII) and its mutant protein variants with the purified gut proteases indicates that carbohydrate binding, presumably to a target ligand in insect gut, and proteolytic resistance are independent properties of rGSII, and that both facilitate its efficacy as a plant defensive molecule.

Preliminary studies on the effect of solar heat on oviposition, development and adult mortality of the cowpea bruchidCallosobruchus maculatus(F.) in the Nigerian savanna

The effect of solarization on oviposition, adult mortality and emergence of the cowpea bruchidCallosobruchus maculatus(F.) was investigated in the Nigerian savanna during the hot season (March–May). Oviposition was significantly reduced as time of exposure to the sun increased, especially in bruchids that were exposed for 3 h, but adult mortality increased with increased exposure time. Adult emergence from eggs that were exposed to the sun 5 days after oviposition (DAV) began was significantly lower than from eggs that were exposed 10 or 15 DAV. Adult emergence was also significantly lower from eggs that were exposed to the sun for 3 h than from those that were exposed for only 1 h.

Uscana lariophaga, West‐African egg parasitoid of the cowpea bruchid beetle Callosobruchus maculatus: photoperiod, parasitization and eclosion interactions

AbstractThe diurnal pattern of parasitization and eclosion of the trichogrammatid Uscana lariophaga Steffan, egg parasitoid of the cowpea bruchid Callosobruchus maculatus (Fabricius) was studied for L12:D12 photoperiods. The wasp parasitized eggs throughout each 24‐h period with about 70% of the parasitization taking place during the first 12 h regardless whether it was the photophase or the scotophase. More female progeny was produced when the first 12‐h period was photophase instead of scotophase. Eclosion of wasps took place over a period of 4 days and occurred during the second half of the scotophase and the first half of the photophase. The number of wasps eclosed during the photophase was similar to that eclosed during the scotophase. Average development time was 8.9 days at 30°C. Male development was completed 6 to 8 h before the females, hence a higher percentage of females emerged in the later eclosion peaks. During scotophases more females eclosed than during photophases. Although the results indicate that the wasp is able to perform under dark storage conditions the effect of permanent low light intensity remains to be studied.