Association of Agrometeorologists

A simple weather based forewarning model for white rust in Brassica

GOPAL KUMAR and N.V.K.CHAKRAVARTY

Field experiments were carried out with two Brassica varieties Pusa Jaikisan and Bio-169-96 (a genotype at the final stages of release) at the Indian Agricultural Research Institute farm during two rabi seasons of 2004-05 and 2005-06. The two varieties were sown on 15th and 30th October. Observations on incidence and spread of white rust were recorded to develop a suitable forewarning model. Incidentally, the 30th October sown plants were found to be infested more by white rust to the tune of 30 and 35 per cent in Bio-169-96 and Pusa Jaikisan respectively, as compared to about 16 and 17 per cent in the 15th October sown plants. A thumb rule was developed to forewarn the incidence of white rust and model equations were developed using hourly weather data of the past to assess the disease severity quantitatively.

Brassica, forewarning model, weather and white rust