Population dynamics of pink bollworm in Bt cotton at middle Gujarat

Abstract

The pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) has major pest on Bt cotton in India. The population dynamics of pink bollworm larvae and damage on different cotton parts i.e., square, flower and green boll were recorded at AAU, Anand, Gujarat during 2019-20 and 2020-21. The infestation of pink bollworm was first recorded from squares during third week of August (33 SMW). The maximum rosette flowers observed during first week of December (49 SMW). The highest green bolls damage noticed during second week of December (50 SMW). Pink bollworm larval population appeared during third (38 SMW) and fourth (39 SMW) week of September and persist throughout the crop periods, reaching peak activity at third week of December (51 SMW) during 2019-20 and 2020-21. The favourable environment conditions for increased pink bollworm population and damage in cotton were, minimum temperature, low vapour pressure, minimum relative humidity, less rainfall, fewer rainy days, high evaporation, and high bright sunshine hours.