Seasonal dynamics of Bemisia tabaci and cotton leaf curl disease in relation to weather parameters in the cotton-growing belt of Haryana, India

Bemisia tabaci (Gennadius), is an important sucking pest of cotton and a vector of cotton leaf curl disease (CLCuD) in northern India. This study characterised seasonal dynamics of adult whitefly and CLCuD and their associations with weather during kharif 2024 and 2025. Bt cotton hybrid RCH-926 (BG-II) was monitored under unprotected conditions from SMW 25–43 in 2024 and SMW 24–43 in 2025. Whitefly abundance was bimodal in 2024, peaking at 44.58 adults per three leaves in SMW 31, with a secondary peak of 25.47 in SMW 38, whereas 2025 showed a predominantly unimodal pattern, peaking at 60.72 in SMW 37. Evening relative humidity showed the strongest positive association with whitefly abundance in both years, although significance disappeared after multiple-testing adjustment. CLCuD reached 100% incidence by SMW 35 and 37 in 2024 and 2025, respectively. Overall, findings support season-specific, continuous surveillance and locally relevant integrated pest and disease management