Feeding potential of green lacewing, Chrysoperla zastrowi sillemi (Esben - Petersen) on two tailed mealy bug Ferrisia virgata (Homoptera: Pseudococcidae) and its bio-safety to insecticides

Abstract

Green Lacewing, Chrysoperla zastrowi sillemi (Esben - Petersen) (Neuroptera: Chrysopidae) is one of the most important natural enemy and has a great role in reducing population of phytophagus insects in field crops and vegetables. Laboratory study was conducted during 2019–20 to record foraging potential of different larval stages of C. z. sillemi against two tailed mealybug Ferrisia virgata nymphs. Predator was found feeding on all the nymphal instars of F. virgata. Feeding potential of C. z. sillemi on the nymphs F. virgata revealed that maximum number of F. virgata nymphs (37.30) was consumed by third instar grub during its developmental period of 3.30 days. A total of 66.87 nymphs were consumed by C. z. sillemi during its total larval period of 9.16 days. The insecticide-tolerance and hatchability of eggs of C. z. sillemi was tested against six different insecticides viz, imidacloprid 17.8 SL (0.00712%), thiamethoxam 25% WG (0.005%), chlorantraniliprole 18.5 SC (0.0037%), fipronil 5% SC (0.01%), spinosad 45% SC (0.0125%) and azadiractin 1% EC (0.02%) having varied formulation used in guava ecosystem to control the pests. Interestingly, the hatchability of the eggs varied from 78.5% recorded in untreated check to 41.0% in imidacloprid 17.8 SL (0.00712%). Treatments were evaluated for their toxicity to C. z. sillemi third instar grubs. After 24 hrs of treatment, maximum grub mortality of 80.0% was encountered in thiamethoxam 25 WG (0.005%) treatment.