Laboratory assessment of influence of alternating temperature on growth and development of Pectinophora gossypiella (Saunders) in Bt cotton

Abstract Pectinophora gossypiella is one of the most destructive pests of Bt cotton. P. gossypiella gradually became a serious threat after gaining resistance to Bt toxin owing to which resulted in huge economic losses to the cotton growers. Present investigation was carried in order to study the most favourable temperature of P. gossypiella for its growth and development under various altering temperature regimes (20:30oC, 24:30oC,28:30oC, 20:35oC, 24:35oC, 28:35oC, 20:40oC, 24:40oC and 28:40oC) in Integrated Pest Management Laboratory, Department of Entomology, PAU, Ludhiana during kharif 2022-23. The results revealed that duration of all larval instars and total larval duration were significantly shorter at an alternating temperature of 28:40oC. The pupal duration, adult longevity and total developmental period of male and female were recorded significantly lower at an alternate temperature of 28:40oC. The fecundity and survivability (egg, larval and pupal) recorded maximum at 28:30oC, whereas the larval and pupal weights were recorded highest at an alternate temperature of 28:35oC. The correlation between developmental parameters and fecundity shown significant negative correlation, the survival of egg, larva and pupa show non-significant negative correlation, whereas the larval and pupal weights show non-significant positive correlation with alternate temperatures.