Effect of Developmental Stage and Density of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) on the Predatory Performance of Four Coccinellid Predators

The predatory performance of four coccinellid predators, viz., Hyperaspis maindroni, Cryptolaemus montrouzieri, Nephus regularis and Scymnus coccivora, was studied on Phenacoccus solenopsis under laboratory conditions at 27 ± 2°C and 65 ± 5% RH. The grubs of all the four predators preferred to prey upon second instar mealybugs followed by third instars and adults when given the choice and fourth instar grubs were the most voracious. The overall predation by the grubs of C. montrouzieri (170.40 mealybugs) was significantly higher than that of the rest of the species. The rate of predation was dependent on developmental period and per day consumption of grubs of all the stages decreased with increase in size of the mealybug. Mean number of P. solenopsis individuals consumed and number of eggs laid per day by the females of all the predators increased gradually with prey density from lower to higher densities, but at a decreased rate.