Sublethal effects of some insecticides on the functional response of Aenasius bambawalei Hayat, 2009 (Hymenoptera: Encyrtidae)

Aenasius bambawalei Hayat, 2009 is one of the most effective natural enemies of Phenacoccus solenopsis Tinsley, 1898. The sublethal effects of dimethoate, imidacloprid, and thiodicarb on the functional response of A. bambawalei to different densities of third instar nymphs of P. solenopsis were evaluated under laboratory conditions. Young females were exposed to the insecticides and then introduced to the host densities of 2, 4, 8, 16, 32, and 64 for 24 h. The results revealed a type III functional response in control and insecticide treatments. The handling time and maximum attack rates of A. bambawalei females were adversely affected by insecticides. The longest handling time and the lowest value of maximum attack rate were observed in thiodicarb treatment, 5.03 h and 4.76, respectively. Therefore, for the simultaneous application of biological and chemical control of P. solenopsis, the influence of insecticides on the functional response behavior of natural enemies must be evaluated.