Laboratory Evaluation of Neem (Azadirachta indica) Seed and Leaf Powders for the Control of Khapra Beetle, Trogoderma granarium (Coleoptera: Dermestidae) Infesting Groundnut

Bioassay evaluation of neem (Azadirachta Indica A. Juss) seed powder (NSP) and neem leaf powder (NLP) against the larvae of Trogoderma granarium in stored groundnut was conducted under open laboratory conditions of 27oC and 70±10% relative humidity. Ripened neem seed fruits and leaves were collected from neem trees, adequately shade-dried, pounded and sieved to obtain fine powder. Treatments were applied at 2.5, 5 and 10% w/w Samnut-22 groundnut seed, with pirimiphos-methyl (2% Actellic dust) as standard check in addition to an untreated control. Larval mortality, progeny emergence, seed damage and viability were assessed. Results showed that NSP was next to Actellic dust in efficacy followed by the NLP; all significantly better than the untreated control in causing greater larval mortality, reduced progeny emergence and seed damage with no harm to seed viability. Actellic dust at 5 and 10% w/w was more effective than the plant materials as 100% mortality was achieved within 24 h post-treatment with no seed damaged. NSP treatment gave 100% mortality only at 10% w/w level with about 6.5% and 6.7% seed damage and progeny emergence respectively, while NLP was the least efficacious giving 50% mortality at 10% w/w, 28% seed damage and 33% progeny emergence in 24 h but better than the untreated control in all the parameters evaluated. © 2010 Friends Science Publishers