Department of Entomology, H.P. Krishi Vishvavidyalaya, Palampur-176 062, Himachal Pradesh (India).
Investigations carried out for four years during 1989–92 revealed that Plutella maculipennis Curtis was prevalent from March onward with its peak activity from the second fortnight of March to first fortnight of April. The peak activity coincided with the active vegetativelflowering and late growth stages of rabi season crops. Although its seasonal abundance was influenced by various weather factors, yet a narrow range of mean maximum and minimum temperatures from 17.9–19.8°C and 10.0–10.8°C, respectively, appeared to be a more predominant factor. The mean relative humidity ranged from 48.8–67.0% during the peak activity.
