Abstract

Bursa and Yalova provinces are very important centers of chestnut production and processing. Chestnut blight is a serious disease of Castanea spp. and the only feasible method to control it is the use of hypovirulence. Hypovirulence and vegetative compatibility (vc) types of 198 isolates of Cryphonectria parasitica obtained from 15 different locations from Bursa and Yalova provinces in three years were determined and discussed. Vc types of C. parasitica isolates were evaluated by using six European vc types; EU–1, EU–2, EU–5, EU–6, EU–12 and EU–14. All strains were found to belong to EU-1 vc type. White mycelial growth which is typical for hypovirulence was observed in 12% of the isolates. All these white-growing isolates were found to contain ds-RNA. Presence of only one fungal vc type and one hypovirus subtype (Subtype I) which was determined by analyzing gene sequences of dsRNA of the hypovirus in our previous work suggests that a possible biological control of the disease might be applied in this region.

Key words: Chestnut blight, Cryphonectria hypovirus, vc types, hypovirulence.