Exploring weather dynamics of Fusarium wilt incidence caused by Fusarium oxysporum in chilli (Capsicum annuum L.)

Abstract

A field experiment was conducted using the Bullet Lanka variety of chilli to evaluate the influence of meteorological variables and different transplanting dates on the incidence of Fusarium wilt of chilli caused by Fusarium oxysporum during the rabi season of 2021-22 at Sriniketan, West Bengal, India. The study employed weather parameters such as the Area Under Disease Progress Curve (AUDPC), apparent infection rate (r), and multiple regression analysis to characterize disease dynamics. A high incidence of the disease was observed at temperatures of 30.72 and 21.58°C, with evening and morning relative humidity (RH) of 68.26 and 72.43%, respectively, and in the absence of rainfall. The AUDPC and apparent infection rate (r) were lowest in the crop transplanted on 15th November 2021, whereas the highest values were recorded in the crop transplanted on 5th November 2021. Correlation analysis revealed that both maximum and minimum temperatures had a positive relationship with percent disease incidence (PDI), while evening and morning RH, as well as rainfall, showed a negative relationship with PDI. Furthermore, the coefficient of determination (R²) obtained from multiple regression analysis indicated that the combined effect of meteorological variables explained 81 to 90% of the variation in disease development across all transplanting dates. The findings highlight the significant role of climatic factors in disease development and provide a basis for developing weather-based prediction models for effective management of Fusarium wilt in chilli.