Biological Control of Solenopsis Mealybug, Phenacoccus solenopsis Tinsley on Cotton: A Typical Example of fortuitous Biological Control

Observations on field incidence of solenopsis mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) attacking cotton and the predators and parasitoids associated with it were recorded in the cotton growing belt of Haryana state by conducting monthly surveys during 2008 and 2009. To assess the impact of primary and secondary parasitoids on the population of the solenopsis mealybug, parameters like severity of pest incidence, abundance of predators and parasitoids and parasitism/hyperparasitism by various parasitoids were taken into consideration. One primary parasitoid, Aenasius bambawalei Hayat, and four hyperparasitoids were recovered. The most abundant and dominant hyperparasitoid was Myiocnema comperei Ashmead, while the other three were of lesser importance. Similarly, out of six predators recovered from mealybug colonies, Brumoides suturalis (Fabricius) and Nephus regularis Sicard were more abundant. During 2008, in the absence of the primary parasitoid, A. bambawalei, mealybug incidence was quite high on cotton. However, during 2009, as the activity of the primary parasitoid increased, the pest population reduced significantly and its incidence was confined to only 18% of the fields and 1.6% of the plants by August. During mid-season (July-August), A. bambawalei was attacked by several species of hyperparasitoids, particularly M. comperei, which caused considerable reduction in its population during August. This resulted in the resurgence of solenopsis mealybug, though on a lower scale, during September-October.