Weather based forewarning of green jassid attack on kharif rice and operational crop protection at Pattambi, Kerala

The feasibility of meteorological forewarning of green jassid attack has been made using entomological and meteorological data for a period of 15 years from 1987- 2001 recorded daily at Pattambi in Kerala. Stepwise multiple regression technique is used in this study for developing forewarning models. The study revealed that maximum and minimum temperature, morning and afternoon relative humidity, bright sunshine hours and weekly totals of rainfall have profound effect on the development of green jassid at their successive generations on kharif rice crop. Weather based multiple regression models for the peak infestation period for each of the generations of the pest were developed using data for the period 1987-99 and validated using observed meteorological as well as pest data for 2000-01. Based on the findings of this study pest weather calendar for green jassid of kharif rice was prepared. This calendar would be useful for early warning and operational rice crop protection from green jassid attack.