Biological studies of pod borer, helicoverpa armigera (hubner) in chickpea

Abstract

Abstract : The biology of pod borer, Helicoverpa armigera (Hubner) in chickpea was studied in the Entomology Laboratory of the Regional Agricultural Research Station, Bangladesh Agricultural Research Institute, Ishurdi, Pabna, Bangladesh at room temperature during February to April 2004. The preoviposition, oviposition and postoviposition periods were 2.25 ± 0.19.'3,45 ± 0.23 and 1.15* 0.08 days, respectively. Females laid 680-1620 eggs singly or 2-6 eggs in a cluster at night during 3.45 days of oviposition period. The hatching percentage . of eggs was 85.77 * 5.19. The incubation period of-egg ranged from 2-4 days. The larva passed through six instars and the durations of 1", 2'*d, 3rd , 4Ih, 5,h and 6,h instar larvae were 2-4. 2-4, 2-3, 1-3, 1-3 and 1-2 days, respectively. The length and breadth of full grown larvae ranged 25.0-36.0 mm and 4.0-5.5 mm, respectively. A period of 10-15 and 9-14 days were required to complete larval and pupal stages, respectively. The longevity of male and female ranged 3-5 and 4-9 days, respectively. The male and female completed its life span (egg to death of adult) between 28-33 days and 29-36 days, respectively. The sex ratio