Abstract:

A total of 6017 single-sclerotium isolates of Sclerotinia sclerotiorum were collected throughout Jiangsu Province in order to determine their sensitivity to Carbendazim and Dimethachlon. From 2006 to 2010, the Carbendazim resistance in S. sclerotiorum was widely spread throughout Jiangsu Province with the resistance frequencies of 63.9%, 24.0%, 17.1%, 16.7% and 9.8%, respectively. Although the resistance frequencies decreased year by year, most of them were highly resistant strains. Moreover, there was no significant difference on the performance of mycelial radial growth, pathogenicity, and sclerotial production between Carbendazim resistant and sensitive strains. In the five years, most isolates were considered sensitive to Dimethachlon. Only six isolates collected in Yancheng, Changzhou and Lianyungang showed normal growth at 5μg/mL. Moreover, the Dimethachlon resistance isolates were less fit than sensitive isolates in terms of mycelial radial growth, pathogenicity, and sclerotial production.