Growth inhibitory effect of Ponneem, a botanical pesticide against the looper Ascotis selenaria Hubner infesting tea in northeast India

Abstract

The efficacy of Ponneem, a commercial botanical pesticide, containing neem oil (40%) + pongamoil (40%) + azadirachtin (1.250ml/L) + emulcifiers (15%) and solvents (5%), was evaluated at 0.5ml, 1.0ml, and 2ml/L against the II instar larvae of Ascotis selenaria in the laboratory. Parameters such as the feeding rate, duration of development and mortality significantly varied among treatments, compared to untreated control. Feeding rate increased with the advancement of instars. The feeding rate per day for II larva was 3.3mg and 36.0mg for III instar on untreated leaves. However, the feeding rate was significantly low when the leaves were treated with the highest concentration of Ponneem and the larvae did not develop further into the next stage. Cent percent mortality occurred within 96h. At lower concentrations, feeding rate was reduced by almost 50% when compared to untreated control. The larval duration was also found to be extended by 5.6-10.6 days, depending on the dose. Except for the lowest concentration and untreated control, the surviving individuals showed deformities by producing larval-pupal, pupal–adult intermediates, indicating the growth inhibitory action of the biopesticide.