Abstract

Field experiments on the incidence of B. tabeel and yellow mosaic of groengram. revealed that more population of white fly and the incidence of the yellow mosaic disease occurred in the crops sown during summer months and maximum was recorded in the crops sown during April. Simple correlation studies of white tly population and yellow mosaic disease incidence with the weather factors revealed that maximum tempe rature was positively correlated with the white fly population at 20 and 30 days old crop and with the disease incidence when the crop was 45 days old. Multiple regression studies revealed that the partial regression coefficient on maximum temperature alone was the important variable in predicting the white fly population one week ahead of the incidence and the partial regression co-efficients on maximum temperature, rainfall and white fly population were the important variables in predicting the disease.

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