Effect of elevated CO2 and temperature on the life cycle of pink bollworm, Pectinophora gossypiella (Saunders) mediated by Bt cotton

Abstract

Pink bollworm, Pectinophora gossypiella (Saunders) is the notorious pest and being a monophagy on cotton, the damage that it causes is alarming. Any changes in the nutritional quality of cotton will have direct influences on pink bollworm. In this regard, the host-mediated effect of eCO2 and temperature on the life cycle of pink bollworm, P. gossypiella on Bt cotton was studied in the open top chambers at the Center for Agro-climatic Studies, UAS, Raichur. The results revealed that variations in phyto-chemistry of Bt cotton particularly the cry toxin expression and nitrogen have reduced in elevated CO2 and temperature conditions which also reduced larval, pupal period, adult longevity, fecundity and incubation period. However, the total life span of pink bollworm did not show statistically significant differences among the climate change treatments. Similar results were noticed when pink bollworm was reared on Bt cotton collected from different open top chambers and reared separately in growth chambers and the same larvae were analyzed for their enzyme activity. A significant increase in the activity of midgut proteases (trypsin and chymotrypsin), carbohydrases (α-amylase) was noticed but lipase activity was reduced.