Development of weather based rice yellow stem borer prediction model for the Cauvery command rice areas, Karnataka, India

Relationship of weather parameters viz., maximum temperature (Tmax, °C), minimum temperature (Tmin, °C), rainfall (RF, mm), morning relative humidity (RH1, %), evening humidity (RH2, %), and sunshine hours (SSH), during seven years at Mandya (Karnataka) was individually explored with peaks of rice yellow stem borer (YSB) Scirpophaga incertulas (Walker) light trap catches. The peaks of YSB trap catches exhibited significant correlation with Tmax of October 3rd week, Tmin of November 1st week, RF of October 2nd week, RH1 of November 4th and RH2 of November 1st week, and SSH of October 4th week. Weather-based prediction model for YSB was developed by regressing peaks of YSB light trap catches on mean values of different weather parameters of aforesaid weeks. Of the weather parameters, only Tmin, RF, and RH1 were found to be relevant through stepwise regression. The model was validated satisfactorily through 8-year independent data on weather parameters and YSB light trap catch peaks (R2 = 0.90, p < 0.0002).