Effect of sowing date and weather parameters on turcicum leaf blight severity and yield in maize.

摘要

Field experiments were conducted during 2003-04 and 2004-05, in Dharwad, Karnataka, India, to determine the effect of sowing date and weather parameters on the severity of turcicum leaf blight (Exserohilum turcicum [Setosphaeria turcica]) of maize and their impact on maize yield. Disease severity gradually increased in the sowings until 16 September and then decrased thereafter. Maximum disease severity (75.37%) was recorded on the crop sown on 16 September, which resulted in significantly lower yield (10.25 q/ha). Crop sown during the first fortnight of April recorded minimum disease severity (26.75%) and significantly higher yield (25.88 q/ha) was obtained with crop sown on 16 April. Relative humidity (>70%), temperature (25-30 degrees C) and rainfall (47-104 mm) influenced maximum blight development. Relative humidity was the most important factor favouring disease development which showed significant and positive correlation with disease incidence while minimum and maximum temperatures had significant and negative correlations.