Biological Control of Sclerotinia Rot Caused by Sclerotinia sclerotiorum in Lettuce Using Bacillus amyloliquefaciens HY

To test the antagonistic ability of Bacillus amyloliquefaciens HY against lettuce sclerotinia rot caused by Sclerotinia sclerotiorum, an in vitro test, greenhouse test and growth chamber test were conducted. As a result of in vitro dual culture test for sclerotia of B. amyloliquefaciens HY, the mycelial growth inhibition rate was 70.7%. Mycelial tip was swollen, black, and had an irregular and deformed shape. In I-plate test, the antagonistic volatile compounds produced by B. amyloliquefaciens HY, the mycelial growth inhibition rate was 57.7% and the sclerotia germination inhibition rate was 46.7%. In addition, B. amyloliquefaciens HY had sideropore production capacity, phosphate solubillibty, and protease production capability, but B. amyloliquefaciens HY did not produce chitinase. In growth chamber test, the lettuce survival rate was 0% in the control group treated with only the pathogen, and 80% in the treatment group treated with of S. sclerotiorum and B. amyloliquefaciens HY by diluting 10 times of the lettuce survival rate. In addition, the lettuce survival rate of 80% was shown in the treatment group treated with the culture medium of B. amyloliquefaciens HY 50 times 1 week later after inoculation with S. sclerotiorum.