Pathogenicity of Rhizoctonia cerealis to Wheat in Jiangsu Province

Different methods for evaluating the pathogenicity of Rhizoctonia cerealis to wheat were tested with 7 isolates of the fungus.According to the results,a preferable method is to sow germinating wheat seeds in the PDA colony of the test isolated and incubated in growth chamber.The disease incidence was as high as 60 4% on average and the difference in disease severity between isolates was significant at the 5% probablility level. 30 isoates of Rhizoctonia cerealis were tested for their pathogenicity to wheat using this method.There were 4 pathogenicy types in these isolates.JR5,JR7,JR44 and other 7 isolates were classified as strong pathogenicity ;9 isolates such as JR127,JR13,JR52 and JR89 et al had less strong pathogenicity ;the pathogenicity of 6 isolates including JR117,JR2,JR47 and JR56 was weak. JR19 and JR22 had no pathogenicity to wheat.