Biology of Pyrilla perpusilla Walker (Homoptera: Lophopidae), A Pest of Sugarcane in the Wet Zone of Sri Lanka

摘要

Biology, life history, preliminary behaviour of mating and egg laying and laboratory rearing of Pyrilla perpusilla Walker (Homoptera:Lophopidae) were studied in University of Kelaniya in the wet zone of Sri Lanka from 1993 July-1994 July. The bug is one of the serious insect pests of sugarcane in Sri Lanka. Female P. perpusilla has a pre oviposition period of 8.8±1.077 days and the average fecundity was 133±10.2 eggs. Eggs are laid in clusters on both the lower (abaxial surface) and upper surfaces (adaxial surface) of sugarcane leaves preferably on lower surface and are covered with white waxy filaments. The eggs are white, oval and have a mean length of 1.04±0.148 mm. Incubation period was 6.9±0.87 days in the field conditions and 6.8±0.81 days in cage conditions. There were five nymphal instars and nymphal phase was 40-60 days. Longevity of the adult female was significantly greater than that of males. Analysis of aggregated sampling data for males and females showed that the sex ratio was 1: 1.