Authors : J. S. Dahegaonkar1 and A. S. Mohite
Page Nos : 186-193
Description :
Life history studies of Helicoverpa armigera were conducted on artificial diet under laboratory conditions at room temperature. The incubation period of egg was 3.42 ± 0.40, varies from 2 to 5 days. The size of the egg was 0.50 mm in length and about 0.48 mm in breadth. The total larval period of all six instars varies from 18 to 26 days and the length of first to sixth instar larvae were 2.58 ± 0.01mm, 3.93 ± 0.08mm, 8.73 ± 0.18mm, 12.03 ± 0.15mm, 22.67 ± 0.43mm and 35.99 ± 0.89mm, respectively. There was variation in colour within larval instars. Full fed larvae pupated by constructing earthen cells in the soil. The pre-pupal period was 3.11 ± 0.27days, varies from 1-4 days. Average pupal period was 13.80 ± 2.87, varies from10 to 16 days. The males were recorded greenish-grey in colour, while females were orange-brown and the longevity of male and female was 7 to 10 (average 8.70 ± 0.55) days and 9 to 13 (average 11.80 ± 0.72) days, respectively.The males outnumbered the females in the laboratory as they comprised 60% of the population. The fecundity varies from 557 to 739 eggsper female. Egg-laying usually begins 3 days after the emergence and were always laid singly.
