Development of American Bollworm, Helicoverpa Armigera (Hübner) (Lepidoptera: Noctuidae) in Relation to Heat Unit Requirement

Abstract

Laboratory Experiment were carried out to study the effect of different temperature's degrees, (15, 20, 25, 27 and 30 °C) on the developmental stages of the American bollworm (ABW) Helicoverpa armigera (Hübner) reared on artificial diet. As temperature increased from 15 to 30 °C the life span decreased. The lower thermal threshold for the development of ABW eggs is 13.01 °C, for larvae is 11.98 °C, for pupal stage is 9.79 °C and for pre-ovipostion period is 12.83 °C. The thermal constant for the development of eggs is 36.69 day degree (DD's), for larvae is 245.17 DD's, for the pupal stage is 181.64 DD's and 34.99 DD's for the pre-ovipostion period. The lower thermal threshold for generation of ABW is 11.54 °C and the thermal constant is 494.39 DD's. Obtained results are essential information for predicting the field population of ABW.

Heat accumulations and sex pheromone traps as a tools for predicting the cotton leaf worm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) field generations at Assiut Governorate

“…At the same trend, temperature is an influencing factor affecting the insect life and activity. This factor may be utilized to gain some insight into the size and behavior of field population and consequently into the history and ultimately prediction of future generation (Ragab, 2009;Amer et al, 2009;Dahi, 2007 andRagab, 2014). Similarly,Duraimrugan and Alivelu (2018)used pheromone trap for determining action threshold of S. liturabased on number of moths catches.…”