MASUM A., HODGSON CJ.
Abstract
The study looked at the residual effect of some commonly used insecticides (e.g.
Ambush, Diazinon and Nicotine) on the mortality and behaviour of Aphidius colemani
Viereck, in particular, whether the latter changed in the presence of sub-lethal
doses of the pesticides. It was found that even at half concentration, the residual
effect of all three insecticides lasted more than the official recommended period,
i.e. 14, 14 and 2 days for Ambush, Diazinon and Nicotine respectively, in that
they all modified the on-plant foraging behaviour of the parasitoid. The results
for Diazinon suggested few effects after 20 days but for Ambush the average
net speed, time spent searching and total time spent on the leaf disc even after
20 DAS was significantly lower. For Nicotine only the number of entries was
significantly lower at 4 DAS.
Key Words:
insecticide, pesticide.