Efficacy of Plant-derived Biopesticides Against Aphids: A Comparative Evaluation of Custard Apple Seed Oil, Neem Oil, Castor Oil, and Tobacco Leaf Extract
Khondoker Mahmudul Huq
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh.
Jenia Afrin
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh.
Md. Asaduzzaman
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh.
S. M. Hemayet Jahan
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh.
Mohammad Atikur Rahman
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh.
Md. Rasal-Monir *
Department of Agricultural Extension, Ministry of Agriculture, Bangladesh.
*Author to whom correspondence should be addressed.
Abstract
The present study evaluated the efficacy of selected plant-derived biopesticides against aphids associated with brinjal, common bean and mungbean under laboratory and pot conditions. Treatments consisted of tobacco leaf extract, custard apple seed oil, castor oil and neem oil, each applied at 2% and 5% concentrations, along with an untreated control. The experiments were arranged in a completely randomised design with nine treatments and three replications. Mortality of brinjal aphid and bean aphid was recorded at 12, 18 and 24 hours after spraying under laboratory conditions, whereas mungbean aphid mortality was assessed at 12-hour intervals for 72 hours in the pot experiment. Among the tested botanicals, 5% neem oil consistently produced the highest aphid mortality. In brinjal aphid, 5% neem oil caused 94.44% mortality at 24 hours, followed by 5% tobacco leaf extract with 83.33% mortality. In bean aphid, 5% neem oil and 5% tobacco leaf extract resulted in 77.77% mortality at 24 hours. In the mungbean pot experiment, 5% neem oil achieved 100% mortality at 72 hours, followed by 5% tobacco leaf extract with 95.87% mortality and 2% neem oil with 89.96% mortality. The untreated control recorded no mortality in all experiments. However, tobacco leaf extract caused visible brown burning spots in the pot experiment, indicating possible phytotoxicity. The findings indicate that neem oil, particularly at 5%, showed comparatively higher efficacy against aphids in this study.
Keywords: Aphid, neem oil, tobacco leaf extract, custard apple seed oil, castor oil, botanical insecticide, mungbean, brinjal, common bean, phytotoxicity