Studies on larval behaviour and diapause of pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera : Gelechidae) on Bt cotton

During the end of kharif 2017-18 season, the larvae entered in diapause in February and March 2018 (34.69 and 43.84%, respectively.). The diapause period of these larvae was 87.50 and 135.65 days, respectively. In the month of September and October 2018, total larvae entered in pupation whereas diapausing larvae were not noticed. While 9.80 to 10.64% larvae entered in diapause in November 2018 and it gradually increased till the end of season. In January and February 2019, the percentage of larvae entered in diapause was 33.33 and 44.44%, respectively. During kharif 2018-2019, the diapause period ranged from 41.95 to 143.20 days. The larvae entered in diapause during January 2019 recoded highest diapause period (143.20 days).