Influence of weather parameters on the seasonal incidence of shoot fly (Atherigona soccata Rondani) on sorghum in Gujarat, India

Abstract

A field study was conducted at the Agronomy Instructional Farm, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar, Gujarat, during the summer, kharif and rabi seasons of 2024-25 to investigate the seasonal incidence of sorghum shoot fly, Atherigona soccata Rondani and its relationship with prevailing weather parameters. The incidence of shoot fly varied significantly among seasons. During summer, infestation commenced in the 13th Standard Meteorological Week (SMW) with 6.67 per cent dead hearts and reached a peak of 36.67 per cent during the 15th SMW. In kharif, infestation began in the 28th SMW with 10.00 per cent dead hearts and attained a maximum of 43.33 per cent during the 32nd SMW, representing the highest seasonal infestation. During rabi, shoot fly incidence started in the 47th SMW with 3.33 per cent dead hearts and peaked at 30.00 per cent during the 50th SMW. Spider populations appeared shortly after crop establishment and fluctuated throughout the crop season. Correlation analysis revealed a significant negative association between wind speed and shoot fly infestation during summer (r = -0.627*), while bright sunshine hours showed a highly significant negative relationship during kharif (r = -0.792**). No weather parameter significantly affected shoot fly incidence during rabi. Multiple regression analysis indicated that weather parameters exerted a greater influence on shoot fly incidence during kharif (R² = 0.83) than during summer (R² = 0.56) and rabi (R² = 0.42).