author(s)
Hadi Husain Khan, Ashwani Kumar and Huma Naz

abstract
Cabbage or headed cabbage (comprising several groups of cultivars of (Brassica oleracea) is a leafy green or purple biennial, grown as an annual vegetable crop for its dense-leaved heads. Cabbage butterfly, Pieris brassicae (L.) has emerged as one of the major insect pest of cabbage. Lot of works has been done by several researchers on the population dynamics and evaluation of synthetic and biological pesticides for its management. In the Lenkoran' region of Azerbaijan the seasonal occurrence, number of generations and percentage of the population entering diapause of Pieris brassicae which were mainly influenced by changes in day length and ambient temperature. The population dynamics of Pieris rapae in Skierniewice and the number of larvae per plant varied from 1.2 to 1.7. Pieris rapae was observed at the beginning of July in all years. In Lipnik, the pest was initially observed at the end of August in 1997, in the second fortnight of July in 1998, and at the beginning of June in 1999. In all years, infestation lasted up to the second half of November, suggesting that two generations developed per year.