Survey for the powdery mildew of black gram [Vigna mungo (L.) Hepper] in parts of Northern Karnataka, India.

Powdery mildew caused by  Erysiphe polygoni  DC is one of the major constraints in the production of black gram, which lead to a potential decrease in yield (40-90%). In order to know the severity of black gram powdery mildew, the roving survey was carried out to know the severity of the disease in five districts of northern Karnataka  viz. , Belgaum, Dharwad, Gadag, Haveri and Uttara Kannada districts during  Kharif  and  Rabi  season of 2012-13.  Maximum mean per cent disease severity (PDI) was observed in Belgaum district (68.72%) followed by Dharwad district (59.73%), Haveri district (52.10%) and Uttara Kannada district (44.59%). Whereas, minimum per cent disease severity (PDI) was noticed in Gadag district (20.23%).