Abstract
Bacterial blight disease severity was recorded on ClM-lIOO, ClM-109, ClM-435, NlAB-78, NlAB-Krishma and SLS-1 cultivated in Rajanpur, D.G.Khan, Muzaffarghar, Multan and Jhang districts of cotton belt of Punjab. Three locations were selected randomly from each of the five districts and bacterial blight disease severity was recorded according to a scale on twenty randomly selected cotton plants of each variety. Environmental data consisted of maximum and minimum air temperature, rainfall and relative humidity and disease severity data. These were subjected to correlation and regression analysis. Environmental parameters and disease severity differed significantly among the districts and cotton varieties respectively. Except maximum air temperature, all the environmental variables were significantly correlated with bacterial blight disease severity. The cotton varieties responded differently to environmental conditions. Maximum disease severity was observed at 26-27 QCminimum temperature, 100-147 mm rainfall and 67- 77% relative humidity. There was a poor linear relationship of varying environmental conditions with disease severity recorded on six varieties in five districts.
