EFFICIENCY OF ORGANIC AND INORGANIC PESTICIDES AGAINST STORED GRAIN INSECT PESTS

The insect pests cause substantial loss of grains in the field and during storage of food grains that worth millions of rupees. Hence, in order to manage stored grain insect pests a combination of organic and inorganic pesticide control materials was selected to check the efficiency against red flour beetle (Tribolium castaneum) and pulse beetle (Callosobruchus chinensis). Total 10 treatments were used, eight different organic bio-pesticides (neem seed, neem leaves, naswar, tobacco, eucalyptus, citrus, dhatura and mint) and one inorganic (naphthalene balls) and control used at 32 ± 2°C and 70 ± 5% RH. The results indicated that three doses of all treatments were used as 5, 10 and 20gm in 50gm grains. Overall, maximum (4.33 ± 1.00%) mortality of red flour beetle was observed using neem seed powder and no (0.0 0 ± 00%) mortality was observed in minte leaves powder. In case of pulse beetle, the maximum (5.07 ± 0.87%) mortality was observed using neem seed powder and minimum (0.66±0.22%) using citrus leaves powder. Maximum (16.26 ± 0.03) antifeedant efficiency of red flour beetle was observed in control group and minimum (6.46±0.65) antifeedant efficiency of red flour beetle was found in dhatura leaves powder at all tested concentrations. Maximum (14.23 ± 0.13) antifeedant efficiency of pulse beetle was determined in control group and and minimum (1.00 ± 0.04) was observed for naphthalene balls at all tested concentrations. Maximum (94.67%) repellency against red flour beetle was observed using neem seed powder and minimum (62.00%) was found in naphathalene balls as compared with their controls. Maximum (81.32%) repellency against pulse beetle was observed using naswar powder and minimum (63.34%) repellency was determined using neem leaves powder as compared with their control group. We concluded that 20% of neem seed powder concentration proved effective to suppress the population of both red flour beetle and pulse beetle.

Gas Chromatography-Mass Spectrometry (GC-MS) based Metabolomics of Promising Chickpea Genotypes against Callosobruchus chinensis (L.)

Background: The pulse beetle, Callosobruchus chinensis L. is one of the main biotic threats to chickpea in both field and storage in the world. The evaluation of chickpea genotypes for pulse beetle resistance has increased motivation for the identification and application of host plant resistance as a critical component of pest management. Methods: In the present study, different chickpea genotypes were evaluated under laboratory conditions to identify the antixenosis, antibiosis and GC-MS based untargeted metabolomics of promising chickpea genotypes to the C. chinensis. Result: Genotype NBeG1004 (36.61 eggs/100 seeds) was less prone to egg laying, while ICCV14872 (180.45 eggs/100 seeds) was the most preferred. However, maximal developmental periods, minimum per cent adult emergence and growth index was observed in ICCV92944 Genotype HC1 showed substantial resistance with maximum phenolic, flavonoid and protease inhibitors content. The results revealed that presence of 9-Octadecenoic acid (Z) in HC1 conferred resistance to C. chinensis. These results show assurance for incorporation into an IPM program against C. chinensis.

Potential of cold plasma to control Callosobruchus chinensis (Chrysomelidae: Bruchinae) in chickpea cultivars during four year storage

Cold plasma has proven itself as a promising method of food preservation by controlling food spoilage bacteria at very low temperatures. It is showing potential for insect control. Synthetic pesticides are mostly used to control Callosobruchus chinensis L. (Chrysomelidae: Coleoptera) to which it has developed resistance. The prospective potential of cold plasma treatment to control pulse beetle infestation of chickpea in the storage for about four years of plasma treatment was studied. The four chickpea cultivars were treated with cold plasma at different power 40, 50, and 60 W each for 10, 15, 20 min. Plasma treated and untreated chickpeas were stored in an airtight ziplock pouch. At regular intervals, the grains were observed for infestation. It was found most effective in controlling the pulse beetle infestation of treated chickpea samples. While plasma untreated chickpeas were attacked and damaged mostly by pulse beetle within the first quarter of the storage study. To avoid the problems created by the use of pesticides cold plasma treatment is found to be the best alternative in the protection of chickpea invasion by pulse beetle during a longer storage period. The findings in the present research may be used for the preparation of legumes which may also soak and cook faster like quick-cooking legumes and preserved for years without invasion of pulse beetle.

Bioefficacy of Three Indigenous Plant Extracts Against Callosobruchus Chinensis L. (BRUCHIDAE: COLEOPTERA)

Results of the evaluation on bioefficacy of three indigenous plant extracts for toxicity and residual effects against the pulse beetle, Callosobruchus chinensis L. (Bruchidae: Coleoptera) showed that the plant extracts had toxic and residual effects for controlling pulse beetle. Mortality and residual effects were statistically different among the plant extracts and doses applied. Neem extract showed the highest adult mortality (36.78%) whereas eucalyptus extract showed the lowest (22.75%). The order of the toxicity of three plant extracts was found as neem > custard apple > eucalyptus. Mortality was found directly proportional to the hour after treatments which increased with the progress of time. Between two solvents, acetone solvent possessed the highest toxicity (mortality 32.95%) but methanol showed the lowest toxicity (mortality 30.56%). The residual toxicity was evaluated on the basis of egg laid, adult emergence, seed infestation and weight loss caused by the insect. The highest residual toxicity was found in neem extract with acetone while the lowest in eucalyptus extract with acetone. Neem extract with acetone and custard apple extract with methanol solvent were found effective to toxic and residual effects against pulse beetle of three plant extracts applied. Asiat. Soc. Bangladesh, Sci. 46(1): 1-12, June 2020

Insecticidal, Oviposition Deterrent and Antifeedant Property of Certain Plant Extracts against Pulse Beetle, Callosobruchus chinensis Linn. (Coleoptera: Bruchidae)

Background: The bruchid Callosobruchus chinensis (L.) is one of the major store grain pest of pulses capable of attacking wide range of legumes viz., green gram, black gram, chick pea and pigeon pea and causes 50 per cent damage during storage within 3 to 4 months. The infestation starts in the field, but heavy damage is done in storage. Hence, the current study was aimed to evaluate the insecticidal, oviposition deterrent and antifeedant activity of certain plant extracts against pulse beetle, C. chinensis under storage condition.Methods: The aquous extracts (10%) of Vitex negundo, Pongamia glabra, Cassia angustifolia and Calotropis gigantea were evaluated against the pulse beetle, Callosobruchus chinensis Linn. were carried out at the Department of Agricultural Entomology, Imayam Institute of Agriculture and Technology, Thuraiyur during 2019-20. The commercial product Azadirachtin was kept as a check and the mortality rate was assessed every 24 Hours after treatment (HAT) for three days.Result: The mortality rate after 72HAT was 85.8-87.5% with V. negundo, followed by C. angustifolia (73.33-80.00%) and P. glabra (70.0-75.0%). Azadirachtin gave 100% mortality of the beetle. The oviposition deterrence percentage for pulse beetle, C. chinensis was found to be highest in Calotropis gigantea (37.66-68.16%) followed by Pongamia glabra (30.91-41.50) and Vitex negundo (7.58-46.75) per cent, respectively. The antifeedant activity for pulse beetle was found to be very high when treated with Azadirachtin where there was no food consumption. This was followed by V. negundo (0.1g) and C. angustifolia (0.2g).

Influence of Morphological Attributes of Cowpea Genotypes on Oviposition of Pulse Beetle (Callasobruchus maculatus F.)

Background: Cowpea is an excellent host for Callasobruchus maculatus (F.). These beetles cause havoc in stored cowpea. They have the habit of cementing their eggs to the surface of the host seeds. Hence, the present study was aimed to the find the influence of morphological characters of cowpea varieties/genotypes on oviposition of the pulse beetle. Methods: The ovipositional preference of C. maculatus on 14 cowpea varieties/genotypes was studied under the free choice condition and the data thus obtained were correlated with the morphological characters like seed shape, colour and texture. Result: Each variety/genotype had a significant effect on egg laying by C. maculatus. Significantly least oviposition was noticed in GC 3 (35.33 eggs), having a rough testa texture and greater number of eggs were found on GC 1612 (117.33 eggs) having smooth texture. The pulse beetle preferred smooth textured seeds for egg laying irrespective of its shape and colour. This was again confirmed by one of the genotypes GC 1702, which belongs to the Holstein group based on the eye pattern of the cowpea, in this genotype the pulse beetle preferred to lay eggs on the smooth brown portion surrounding the hilum than the wrinkled white portion.