Epidemiology studies of stem rot of groundnut caused by Sclerotium rolfsii Sacc in Andhra Pradesh ​​

Abstract

Stem rot in groundnut is one of the major diseases significantly affecting the crop yields leading to 10 to 25 per cent yield loss annually. Favourable weather parameters influence development and spread of the disease and the present study was conducted to quantify their role in disease development. Study conducted at Banavasi village of Yemmiganur in Kurnool district, Andhra Pradesh during rabi 2020 and 2021 to know the influence of weather parameters on stem rot disease progression and the relation between leaf spot and stem rot disease development using correlation and regression analysis. A positive correlation of the stem rot with weather parameters like T max, Rainfall, Relative Humidity in rabi, 2020, Relative humidity during rabi, 2021 and negative correlation with Tmin and Wind speed in rabi, 2020, and Tmax, Tmin and rainfall in rabi, 2021 was observed. A regression analysis of the data inferred that the weather parameters as a whole contribute about 66.00% and 60.00% to disease incidence in rabi 2020 and 2021 respectively, of these Tmax (62.37%) and Rainfall (26.12%) in rabi 2020 and Tmin and rainfall during rabi, 2021. Highest stem rot incidence was recorded in 4th standard week (22nd to 28th January) with a per cent disease incidence of 6.78 during rabi, 2020 and in 52nd standard week (24th to 31st December) with a percent disease incidence of 3.6 during rabi, 2021. Initiation of leaf spot has started early i.e., 48th standard week during rabi, 2020 and 49th standard week during rabi, 2021. A non-significant positive correlation between the stem rot and leaf spot in both the years reveal that the diseases developed were solely due to influence of weather parameters on the individual disease and both the diseases are not interrelated or interdependent in causing the other.