The effect of application ofAzadirachta indica andPongamia glabra leaf extracts on food consumption and utilization in fifth instar larvae ofEuproctis fraterna, a serious lepidopterous pest on castor,Ricinus communis, is assessed. Reduction in food consumption byEuproctis fraterna feeding on castor leaves treated with extract ofAzadirachta indica was 11% higher than that recorded for castor leaves treated withPongamia glabra. Consumption, assimilation, production and their rates showed a negative correlation with the concentration of the extracts used.
The effect of administration of these two leaf extracts on efficiency of the digestive enzymes invertase, amylase and protease ofEuproctis fraterna was also assessed. A reduction in activity of these enzymes with the administration of increasing concentration of extracts was also observed.
Leaf extracts of neem andPongamia appear to be most efficaceous in controllingEuproctis fraterna especially when they are administrated along with castor leaves in the fifth instar providing a suitable alternative to synthetic pesticides.