Biology and predatory potential of coccinella arcuata fabricius (coccinellidae : coleoptera) a predator of the brown plant hopper nilaparvata lugens stal.

Abstract

The details of biology and feeding capacity of Coccinella arcuata Fabr,, a predator of Nilaparvata lugens stal were studied under laboratory conditions at 28 ± 1.5° C and 80 ± 2% RH, The mean fecundity was 210 per female. The incubation period of eggs lasted for 3 days. There are four larval instars occupying 12 days followed by a pupal period of 5 days. The total life span from egg to adult emergence lasted for 20 days. The different stages in the life cycle have been discribed. On an average the freshly emerging first iru.tar grub ate first and second instar nymphs of N- lumens at 15 per day. The second, third and fourth larval instars and the adults consumed all nymnhal stages of the host at 18, 25, 27, 29 per day respectively. The adults occasionally feed on adult hoppers. The predatory population was maximum during February - March occurring on the 'Punja' rice crop.