Preliminary Exploration for Growth Characteristics and Fungicide Resistance of Sclerotinia Sclerotiorum in Soybean

Sclerotinia stem rot of soybean caused by the fungus Sclerotinia sclerotiorum was a world wide disease of soybeans in the soybean growing regions.Pure culture isolations of S.sclerotiorum were obtained by single sclerotium.Growth characteristics and fungicide resistance of S.sclerotiorum were determined by using mycelium growth rate method.The seven S.sclerotiorum collected from various locations of Heilongjiang province were used to determine growth characteristic and resistant to carbendazim and procymidone.The results indicated that optimal temperature of mycelium growth and sclerotia production was 15-20℃ and 15℃,respectively.The optimal environment of mycelium growth was neutral and acidic.The result indicated that S.sclerotiorum on plant residues couldn't overwinter,but Sclerotia could overwinter.S.sclerotiorum isolates were differed pathogenicity to eggplant,sunflower,rape and soybean.H6 isolate was more virulent than the others.The results of sensitivity to carbendazim indicated that the EC50 values of S.sclerotiorum strains ranged from 0.5022 to 0.3525 μg·mL-1 and the EC50 of most insensitive fungus was 1.42 folds than the EC50 of most sensitivity.The results of sensitivity to procymidone indicated that the EC50 values of S.sclerotiorum strains ranged from 1.0 230 to 0.4 388 μg·mL-1.The EC50 of most insensitive was 2.33 folds than the EC50 of most sensitivity.The above results suggested that resent S.sclerotiorum isolates collected from various locations of Heilongjiang province didn't produce resistance to two fungicides.The experiments has laid solid theoretical foundation for further research work of biological characteristics and scientific prevention and control of S.sclerotiorum.