The preference, diagnosis, and determination of white root disease caused by Sclerotinia sclerotiorum (Lib.) de Bary in lettuce cultivation areas in Tokat

This study was carried out in order to determine the prevalence of white rot caused by Sclerotinia sclerotiorum, to identify the causative agent, and to reveal the mycelium compatibility groups between isolates in the lettuce production areas of Merkez, Erbaa, Niksar, Pazar and Turhal districts in the province of Tokat. In the survey study carried out between May and July in 2019, white rot disease was found intensively in the areas where lettuce is grown in the province of Tokat. In the survey study carried out in a field of 72 da, the disease density ranged between 9.8-27.45%. The isolations made 51 Sclerotinia sclerotiorum isolates were obtained. the 51 isolates obtained were compared within themselves and with the isolates from other localities, and 3 mycelium compatibility groups were identified. In addition, selected isolates were isolated on lettuce leaves, and their virulence was determined according to the diameter of the lesion on the leaf. There were no statistical differences in virulence among the isolates obtained. ın conclusion, this study showed that S. sclerotiorum is present in almost all areas and that the disease should be identified earlier in order to control this factor. In addition, in order to minimize product losses, it is necessary to determine the best control methods.