Abstract

GROWTH INHIBITORY EFFECTS OF NEEM ON THE PHYTOPHAGOUS PEST HENOSEPILACHNA VIGINTIOCTOPUNCTATA (Fab.) ON BITTERGOURD

R. Shanmugapriyan* and Jaiby Cyriac

Abstract

Azadirachta indica (A.Juss) plant extracts were tested for their growth inhibitory effects on the phytophagous pest Henosepilachna vigintioctopunctata (Fab.) on bittergourd. In this research neem oil and extracts of neem cake, seed kernel, seed coat and bark powder were evaluated. Fed with leaves of bittergourd treated with neem oil 0.25 to 2.5% resulted 90.0% inhibition on adult emergence, 70.0% of pupal mortality and 20.0% of adults with deformities. 2.5% concentration of neem seed kernel extract inhibited the adult emergence upto 56.6%. The growth inhibitory effect of neem cake extract at 0.25 to 2.5% concentration was 10.0 to 46.6%. Bio-efficacy of neem oil on adult emergence is followed by extracts of neem seed kernel, neem cake, neem bark powder and neem seed coat. Extracts of neem bark powder and seed coat were moderately effective on the growth of epilachna beetle. Neem seed coat and bark powder extracts at 2.5% concentration inhibited the adult emergence upto 30.0 and 36.6%. The growth inhibitory effect of neem extracts on adult emergence is directly proportional to the increase of concentration. All the tested neem extracts affected the normal adult emergence by showing morphological deformities in the wings and the shape of the insect. Because of these versatile biological impacts, cost effectiveness and the bio-degradable nature, neem derivatives are suitable component for the bitter gourd IPM schedule.

Keywords: Adult emergence, Adult malformation, Henosepilachna vigintioctopunctata, Integrated Pest management (IPM), Neem derivatives, Total inhibition.