Population dynamics and management of aphid (Aphis gossypii Glover) in bitter gourd (Momordica charantia L.)

Abstract

Bitter gourd (Momordica charantia L.) is an important cucurbitaceous vegetable cultivated widely in India, valued for its high nutritive and medicinal properties. However, its productivity is severely constrained by insect pests, particularly aphids (Aphis gossypii), fruit fly (Dacus cucurbitae), red pumpkin beetle (Aulacophora foveicollis), epilachna beetle (Henosepilachna vigintioctopunctata), and others. Among these, aphids not only cause direct damage through sap feeding also act as vectors of viral diseases, resulting in significant yield reduction. A field survey was conducted at Kadachanenthal and Vadipatti in Madurai district from August to June to study the population dynamics of aphids and their correlation with abiotic factors. Aphid incidence showed significant variation between locations. The maximum population (5.28 aphids/3 leaves) was recorded during the third week of April at Kadachanenthal, while the lowest (0.69 aphids/3 leaves) was observed during the second week of October at Vadipatti. Maximum temperature exhibited a significant positive correlation, whereas rainfall showed a negative correlation with aphid population. Two field experiments were conducted to evaluate the efficacy of newer insecticide molecules and biopesticides against aphids in bitter gourd under randomized block design. Among the newer insecticides, Spinosad 45% SC @ 160 ml/ha proved most effective, recording the lowest aphid population (1.56 aphids/3 leaves) and 93.6 per cent reduction over control. Chlorantraniliprole 18.5 SC @ 150 ml/ha was the next
best treatment. Among biopesticides, Neem Seed Kernel Extract (NSKE) 5% and neem oil 3% significantly reduced aphid population, recording 84.80 and 82.81 per cent reduction over control, respectively, and were comparable to the standard check, malathion. The study concludes that spinosad is highly effective among newer insecticides, while NSKE 5% offers an eco-friendly and safer alternative for aphid management in bitter gourd, helping to reduce reliance on synthetic insecticides and conserve pollinators.