Natural Parasitization of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) on Cotton by Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae)

Abstract

Studies were conducted during 2007 and 2008 over a considerable geographical area under cotton cultivation for finding potential natural enemies of Phenacoccus solenopsis Tinsley. In July 2008, large numbers of mummified P. solenopsis along with healthy mealybugs were observed on heavily infested cotton crop at Central Institute for Cotton Research, Regional Station, Sirsa (Haryana) due to parasitization by Aenasius bambawalei Hayat, a potential bioagent of P. solenopsis. The parasitoid completed its life cycle on the mealybug leaving the mummified body along with the exit hole behind. The parasitization efficiency of the parasitoid from field collected mealybugs was 57.2 per cent (range 46-64%) whereas under laboratory condition, it was 60.6 per cent (45-74%). As biological control is a supplement to chemical control, the adverse effect of commonly used insecticides on cotton on the efficiency of this parasitoid was studied and monocrotophos was recorded as the most deleterious (57.52% reduction in parasitization). Spinosad and spirotetramet were found to cause the least reduction in parasitization.