EFFECTS OF VARYING TEMPERATURE ON THE REPRODUCTION AND SURVIVAL OF MEALYBUG PARASITOID, AENASIUS ARIZONENSIS (HYMENOPTERA: ENCYRTIDAE)

Abstract

Host parasitoid interactions in insects offer some innovative opportunities for the development of successful biocontrol programmes in field crops. Aenasius arizonensis (Girault) is a species specific, solitary endoparasitic wasp of the cotton mealybug, Phenacoccus solenopsis Tinsley and a potential insect control tool. Effects of temperature on different biological traits of A. arizonensis were studied at different constant temperatures i.e., 20±2 ̊C, 25±2 ̊C, 30±2 ̊C and 35±2 ̊C with a relative humidity of 65±5%. Host insects/mealybugs were reared on sprouted potatoes or pumpkins. Total developmental period of the parasitoid at different constant temperatures was recorded with the daily parasitization rate (number of host insects parasitized). At respective temperatures, oviposition and post-oviposition periods were also observed along with the longevity of the male and female wasps. Sex ratio (male: female), reproductive rate, intrinsic rate of increase, and finite rate of increase were also determined at all temperatures. The most favorable temperature for the development and reproduction of the parasitoid was observed as 30±1oC. The information obtained from this preliminary study will be helpful in establishing a mass rearing programme for the parasitoid leading toward sustainable insect pest management of cotton mealybugs in economically important crops.