Bioefficiency of Nimbecidine and TNAU neem on cowpea ahid Aphis craccivora (Koch) applied to fieldbean

Abstract

Two field trails were conducated at Tamil Nadu Agricultural University (TNAU), Coimbatore during 1996-97 to evaluate the effectiveness of Nimbecidine 0.03% EC and TNAU Neem 0.03% EC in comparision with methyl demeton against the field bean aphid Aphis craccivora Koch. The mean per cent reduction of A. craccivora field population, by the neem formulaions was to the extent of 50.2-96.0, 43.4- 89.1, 11.2-67.2 and 1.0-28.1 per cent on 1,3,7 and 14 DAT (Days after treatment) respectively when compared to 95.6-99.7, 91.2-97.2, 74.6-87.5 and 51.9-63.4 per cent by methyl demeton at 1,3,7 and 14 DAT. Both the neem formulations were comparable in their efficacy. The effectiveness of the formulations increased with increase in dose from 200 ml to 1000 ml/ha and decreased as the days advanced. The order of efficacy was Methyl demeton 25 EC>Nimbecidine 0.03 EC-TNAU Neem 0.03 EC.