First instar larvae of spiny cottcn boll wonn Earias insulana
(Bosid.) were Fed on different concentrations of biological insecticides (Agerin) and growth regulators (Match) for ( 5, 3 and one days) .The results showed that Agerin at 1.5 giL caused 99.9 , 99.9. and 96.9 % accumulative killing percentages while 0.5 g/L of this biological insecticidt::s resulted in 92.96 , 58.9 and 33.3% in the three periods of feeding above respectively . On the other hand growth inhibitor (Match) gave 99.9, 99.9 and 99.9 %accumulative killing percentage when it was used at 1.5 ml I L ; whereas the percentages
were 99.9 , 66.6 and 46.6 % when it was used 0.25 ml JL. in the same
periods respectively . Results implied also that accwnulative killing
percentages were increased with the dose and the nutritive periods . Most of the larvae died when they where fed by (match) for 5 days by using high concentrations of both insecticides, it also observed that these larvae did not complete their growth stages , yet when they were fed for 3 or one day by using low concentrations, they were able to complete there life cycle accompanied with delay of larvae stage period and abnormal behavior of the larvae in their color, slow movement and less appetite. The growth regulator (Match) however, was more effective in mortality percentage for the larvae stage as compared with biological insecticide (Agerin).
