effects of amitraz, buprofezin and propargite on some fitness parameters of the parasitoid encarsia formosa (hym.: aphelinidae), using life table and iobc methods

the side-effects of amitraz, buprofezin and propargite were studied on encarsia formosa (gahan)in the laboratory, using a life table response experiment and the iobc system for their toxicity. bioassayswere conducted by dipping bean leaves containing third instar nymphs of the whitefly trialeurodesvaporariorum (westwood), parasitized by e. formosa, in insecticide solutions or caging adult parasitoidsin treated petri dishes. the insecticide buprofezin caused 19.87% and 11.87% mortality in adults andpupae respectively. amitraz showed the highest level of toxicity for the adults (100% mortality) and thepupae of parasitoids (83.3% mortality). both buprofezin and propargite caused no adverse effect on thefecundity and longevity of parasitoids, but amitraz significantly reduced the fecundity and longevity ofadults. life table assay indicated that buprofezin and propargite have no major impact on the intrinsic rateof natural increase (rm), while amitraz lowered the rm value by 7.03%. according to the iobcclassification of toxicity, buprofezin was found to be harmless for the pupae and adults and amitrazproved to be harmful for adults. based on both the life table and iobc methodology, buprofezin andpropargite are found to be relatively safe for e. formosa and can be used in integrated pest managementprograms where this parasitoid is involved.