Temperature effects on the rate of development of life stages of gram pod borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

Life stages of Helicoverpa armigera (Hubner) were held in constant temperatures ranging from 15°C to 30°C to determine the effect of temperature on development, oviposition and fecundity. Over the temperature range tested, developmental rate of the life history stages and oviposition period decreased as temperature increased from 15°C to 30°C. By means of linear regression, a lower developmental threshold temperature of 11. 5°C, 12. 2°C, 13. 4°C and 6. 5°C was estimated for the incubation of eggs, development of larval stage, development of pupal stage and oviposition period, respectively. A mean thermal constant of 45. 53 degree-days, 195. 98 degree-days, 142. 62 degree-days and 81. 53 degree-days above estimated lower threshold temperature was required for the incubation of eggs, larval development, pupal development and oviposition period, respectively. Fecundity was positively correlated with temperature. Maximum oviposition occurred between 25°C and 27°C, however, temperatures of 30°C or higher were detrimental.