Morphometrics and Annual Life Cycle of Greenhouse Whitefly [Trialeurodes vaporariorum (Westwood)] in Himachal Pradesh

Abstract

Morphometrics and life cycle of Trialeurodes vaporariorum (Westwood) was studied under laboratory conditions in mid-hill regions of Himachal Pradesh. Eggs measured 0.201 mm in length and 0.096 mm in breadth. There were three nymphal instars with the corresponding average length&breadth of 0.267&0.145, 0.370&0.217 and 0.658&0.377 mm. The second and third nymphal instars possessed setae like projections. The pupa measured 0.728 mm in length and 0.415 mm in breadth. It was flattened and oval like a scale initially and became opaque and expanded with sub-marginal and dorsal setae later. The females were larger (0.963 mm) than the males (0.844 mm). Under laboratory conditions, the pest completed 13 overlapping generations in a year. Total developmental period was of shorter duration (20.7-27.7 days) in summer and rainy-season generations than in winter generations (33.3-43.3 days). The survival in different generations varied from 36.7-74.2 per cent, being comparatively more in winter generations. The females laid 108-373 eggs in different generations, the fecundity being comparatively more during winter generations.