Effect of Azadirachta indica neem seed kernel extracts on Anopheles dirus mosquitoes

Neem oil (seed kernel extract) produced a strong repellent action on An. dirus mosquitoes (the major vector of malaria) in Myanmar even at concentrations as low as 0.5 and 1.0 percent. At a concentration of 2 percent no anopheles biting and the protection provided was 100 percent during 10-12 hrs periods. The larvicidal effects of neem oil on An. dirus (larvae) were determined by using 3rd instar and above. The LC90 and LC50 were found to be one percent and 0.45-0.5 percent respectively, The residual effect of neem oil under laboratory condition with 2 and 4 percent persisted ca 72+/-5 hrs. Moreover, under laboratory condition with 2 and 4 percent, the ovicidal effect was found to be 100 percent control.