Seasonal incidence and weather based forecasting model for mango leaf webber Orthaga eudrusalis walker (Lepidoptera: Pyralidae) under subtropical conditions

Abstract

A field experiment was conducted for two consecutive seasons (2013 and 2014) in Lucknow, Uttar Pradesh to study seasonal incidence and develop weather based forecasting model for mango leaf webber. A wide variation was observed in the leaf webber incidence across fixed plot orchards, standard meteorological weeks (SMW) and between two seasons. The peak incidence of leaf webber was found during the 37th SMW during the year 2013 with 9.7 webs per tree, whereas, in the consecutive season its peak incidence was observed during 38th SMW with 3.5 webs per tree. Mango leaf webber incidence was found to be significant negative correlation with minimum temperature (r = - 0.39 * * ), wind speed (r = - 0.48 * * ) and positively correlated with the minimum relative humidity (r = 0.37 * * ). Compare to linear models, polynomial models had explained highest amount of variation. Minimum temperature, minimum relative humidity along with wind speed had explained 36 per cent of variation in the leaf webber incidence. Hence, the weather based forecasting model for the leaf webber (Y) for Lucknow region is Y = 31.90 - 1.35 × minimum temperature - 0.72 × wind speed + 0.08 × minimum relative humidity (R2 = 0.36; F = 4.20 p< 0.01). This prediction model after validation can be utilized in the agro advisories for predicting the incidence and timely management of leaf webber.