Influence of weather variables on the incidence of sigatoka leaf spot of banana in Jorhat district of Assam

Abstract

Sigatoka (Emusae leaf spot) of banana (Pseudocercospora musae) perfect stage (Mycosphaerella musicola) is one of the most important diseases of banana, particularly in humid tropics and sub humid tropics. This has been a major problem in the state of Assam where 155 ha of land is under banana cultivation yielding 1315 tonnes of banana per year. Jahaji, Borjahaji and Malbhog are the commercial varieties in Assam and recorded to be susceptible to diseases and yield loss is reported to 50 percent and above recorded from Assam against the disease. Spraying of effective fungicides singly or in combination yielded good results in obtaining higher yield. However, timely application of the fungicides is not practiced by the growers due to lack of information on disease forecasting. Efforts have been made to compile the information on disease intensity for a considerable period of 20 years to forecast the disease by Spearman’s Rho Test, Linear Regression Test, methods. Studies with Spearman’s Rho Test, Linear Regression Test relative humidity during morning time and temperature followed by summer and pre monsoon months (April, May, July, August) are the most important and crucial factors for disease development.