Incidence and Intensity of Early Blight in Potato under Different Dates of Planting

Aim: The study aims to the progression of the early blight of potato in relation to weather parameters such as maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity, and rainfall.

Place and Duration of Study: Epidemiological investigation was conducted during rabi season of 2021-22 at the research field of the All India Coordinated Research Project (AICRP) on potato, OUAT, Bhubaneswar.

Methodology: The trial was laid out in Split Plot Design with different dates of planting (26 November and 16 December), as the main plots and four varieties (Kufri Pukhraj, Kufri Khyati, Kufri Surya, and Kufri Jyoti) as the subplots.

Results: The initial infection of early blight occurred during 52 Standard Meteorological Week (SMW). The highest percentage of disease intensity and incidence occurred in the variety Kufri Pukhraj followed by Kufri Khyati, Kufri Jyoti and Kufri Surya under 26 November planting.

Conclusion: Minimum and maximum temperatures and minimum relative humidity had a significantly positive correlation with the incidence and intensity of early blight. Stepwise multiple linear regression equations revealed that maximum temperature, maximum and minimum relative humidity, and rainfall was responsible for early blight in potatoes.