A laboratory experiments had been conducted to study the toxic effect of lethal and sublethal concentrations of four insecticides (chlorpyrifos, spirotetramat, buprofezin and pyriproxifen) on the ectoparasitoid Aphytis lingnanensis and the endoparasitoid, Encarsia citrina. The obtained results indicated that the residual effect of chlorpyrifos, spirotetramat and buprofezin at the recommended concentration of (675, 40 and 250) ppm, respectively caused more than 90 % mortality to the parasitoid,A. linganensis, while, pyriproxifen (50 ppm) was the least toxic product caused 85% mortality. Chlorpyrifos was the most toxic compound to the parasitoid,E. citrina female,caused 100% mortality followed by spirotetramat (98.3%), buprofezin (95%) and pyriproxyfen (90%), respectively. Chlorpyrifos, buprofezin, pyriproxifen and spirotetramat at a concentration of 33.75, 12.5, 5 and 2 ppm, respectively had low toxic effect on the parasitoid females with no significant differences between the exposed and non-exposed (control) parasitoid females. The searching rate and mutual interference value of A. lingnanensis female treated with buprofezin was affected in comparison with those treated with the other tested compounds. Sublethal concentrations of pyriproxyfen and spirotetramat exhibited a slightly adverse effect on the searching behavior of E. citrina. On the contrary, the searching rate of the parasitoid females treated with chlorpyrifos and buprofezin was adversely affected. Reactions of A. lingnanensis and E. citrina adult females exposed by contact to sub lethal concentrations of the tested insecticides were observed in response to their hosts (A. aurantii and Q.perniciousus). Pyriproxyfen followed by spirotetramat did not significantly affected the behavior response (host recognition) of A. lingnanensis and E. citrina adult females to their hosts.