M Sc

The research work entitled “Evaluation of new generation insecticides and botanicals against pulse beetle Callosobruchus chinensis Linnaeus. (Coleoptera: Bruchinae) was done at the Department of Agricultural Entomology, College of Agriculture, Vellayani, Kerala Agricultural University during 2019-2021. The objectives of the study were evaluation of new generation insecticides, botanicals and botanical formulations against pulse beetle in storage.
The present study was done with botanicals viz., neem leaves (Azadirachta indica), pongamia leaves (Pongamia pinnata), citrus leaves (Citrus spp.), citrus fruit rind (Citrus spp.), lantana leaves (Lantana camera), siam leaves (Chromolaena odorata), hyptis leaves (Measosphaerum suaveolens) and panal leaves (Glycosmis pentaphylla). Dried plant parts of mentioned botanicals (50 g/500 g of grain) were evaluated on grub and adult population of pulse beetle in household storage. After 60 days of treatment maximum percentage of population reduction (both grub and adults) over untreated control was seen in treatment with neem leaves (67.28 and 69.72, respectively) and also reduced the grain infestation by 66.54 per cent over control. Treatment with pongamia leaves showed 61.77 and 62.38 per cent reduction of grub and adult population over untreated control, respectively and also shown 63.67 per cent reduction in grain infestation over untreated control.
Powders of afore mentioned botanicals were also evaluated against pulse beetle to see their efficacy in terms of mortality, repellence, ovipositional deterrence, weight loss and grain damage at three doses (2.5, 5.0 and 7.5 per cent w/w). The highest percentage of mortality (88.33), repellence (66.66) and ovipositional deterrence (100) were observed in treatment with neem leaf powder (7.5 %) and pulse beetle was unable to feed on the grains treated with neem leaf powder (7.5 %) showed highest antifeedant effect (no weight loss and damage). It was followed by treatment with pongamia leaf powder (7.5 %) which induced 76.66 per cent mortality, 50 per cent repellence, 93.00 per cent ovipositional deterrence, 2.6 per cent weight loss and 4.0 per cent grain damage.
Botanical formulations (3 % and 5 % concentrations) of plant extract of Andrographis paniculata (PEA) + Triton X-100 (T) (9:1), PEA+ neem oil + T (7:2:1), PEA+ Pongamia oil + T (7:2:1), neem oil + T + water (2:1:7) and pongamia oil + T + water (2:1:7) were used. These formulations were evaluated against pulse beetle in invitro conditions by topical application on filter paper which was kept in Petri plate and released with 25 newly emerged beetles and percentage of mortality has taken 24,48 and 72 hours after treatment. There was an increasing trend observed in percentage of mortality with increase in concentration. Highest percentage (100.00) of mortality was recorded in treatment with neem oil + T + water (2:1:7) (5 %). It was followed by treatment with PEA+ neem oil + T (7:2:1) (5 %) (97.33 per cent). These two were used to evaluate their efficacy against pulse beetle in storage.
Botanical formulation that showed highest percentage of mortality were evaluated in storage to see their effect on grub and adult population of pulse beetle. The treatment with 5 % concentration of neem oil + T + water (2:1:7) and PEA+ neem oil + T (7:2:1) were sprayed on cloth bag containing 500 g of grains and twenty adult beetles in the ratio of 1:1 (female and male). The treatment with PEA+ neem oil + T (7:2:1) had reduced the percentage of grubs and adult population by 76.14 and 66.66, respectively. Whereas treatment with neem oil + T + water (2:1:7) recorded 72.17 and 63.49 percentage reduction of grub and adult population, respectively over untreated control.
New generation insecticides viz., chlorantraniliprole 18.5 % SC, 1.5 ml/L, thiamethoxam 25 WG, 1g/L, clothianidin 50 % WDG, 1.25 g/L, diafenthiuron 50 % WP, 6g/L, imidacloprid 17.8 % SC, 1.5ml/L and malathion 50 % EC, 10 ml/L. All these were evaluated against the pulse beetle in storage by spraying on cloth bag containing 500 g of grains and twenty adult beetles in the ratio of 1:1 (female and male). All the treatments were superior in reducing the grub and adult population of pulse beetle over untreated control. Treatment with chlorantraniliprole 18.5% SC shown highest percentage of population reduction in comparison to all other treatments. Chlorantraniliprole 18.5 % SC had reduced the grub and adult population over untreated control by 83.09 and 81.59 per cent, respectively. It was followed by treatment with malathion 50 % EC (82.25 and 81.04), imidacloprid 17.8 % SC (78.50 and 78.02) and thiamethoxam 25WG (77.41 and 76.65). Grain damage was greatly reduced compared to untreated control that was ranged from 61.28 to 78.22 per cent.
From the present study it was revealed that botanicals (neem and pongamia), botanical formulations (5% concentration of neem oil + T + water (2:1:7) and PEA+ neem oil + T (7:2:1)) and new generation insecticides (chlorantranilliprole 18.5% SC, 1.5ml/L and malathion 50 % EC, 10 ml/L) were effective in managing pulse beetle C. chinensis with only less damage in comparison with untreated control and had not shown any detrimental effect on viability and no phytotoxicity symptoms were observed after 60 days of storage.

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