Fariba Sohrabi

Compatibility of pesticides and biological control agents is the main concern of Integrated Pest Management (IPM) programs. The present study focused on the side effects of spirotetramat and chlorpyrifos on the demographic parameters of Aenasius bambawalei Hayat (Hym: Encyrtidae). Adult parasitoids were exposed to one ppm of chlorpyrifos and 7.5 ppm of spirotetramat for 24 hours. Then, they were released on the third instar nymphs of the mealybug Phenacoccus solenopsis Tinsley (Hem. Pseudococcidae) and their demography was investigated. The results showed that oviposition period, fecundity, and female and male longevities adversely were affected by both insecticides. However, the adult pre-oviposition period (APOP), the total preoviposition period (TPOP), and the number of daily eggs of insect females were not affected significantly. The intrinsic rate of increase (r) was calculated to be 0.16, 0.13, and 0.12 day-1 for control, spirotetramat, and chlorpyrifos treatments, respectively. The results of this study revealed that chlorpyrifos at sublethal concentrations have more negative effects on A. bamabawalei than spirotetramat and need to be applied with caution in IPM programs.