Severity of grape powdery mildew caused by Uncinula necator (Schw.) Burr. in grape growing areas of Northern Karnataka.

摘要

A survey was conducted to assess the severity and distribution of grape powdery mildew (Uncinula necator) in vineyards of northern Karnataka, India, after October pruning during 2002-03 at vegetative, flowering and fruiting stages of the crop. Some vineyards in the villages of Koppal (Mudhola, Hiremageri and Hosur), Bagalkot (Benakatti, Kaladgi and Mallapur), Bijapur (Bijapur, Honawad, Hitnahalli, Jumnal, Kalebagh and Thidagundi) and Raichur (RARS Farm) districts were selected. Powdery mildew severity was recorded on foliage and berries of different cultivars. Manik Chaman showed the maximum disease severity, followed by Thompson Seedless and Sonaka. Bangalore Blue recorded the least disease incidence at Raichur. Vineyards at Hitnahalli recorded the maximum percentage disease index (PDI) of 42.99 and 57.14 on foliage and 3.37 and 20.20 on berries during week 1 of January 2003 and week 1 of March 2003, respectively. A high disease intensity was observed in Thompson Seedless, and no disease in Sharad Seedless. Irrespective of the cultivars, the maximum PDI was noticed in Raichur (71.16), followed by Bijapur (46.12), Koppal (36.19) and Bagalkot (5.34)..