Application And Selection Of Biocontrol Bacterium Against Sclerotinia Sclerotiorum

The soybean sclerotinia stem rot is a serious disease in main soybean growing area inHeilongjiang province. The disease infection occurs mainly in soybeans after sealing ridge. Thechemical control is difficult to inhibit this kind of disease, which mainly occur on stem, because ofthat soybean leaves prevent of the pesticide falling on the infected site. For this trait of thedisease bio-control is of optimum measure definitely. Compare with chemical control,bio-control which owned more merit, including non-residual, safety, no-pollution and so on. In thisstudy, microbical strains for control soybean sclerotinia stem rot were screened and theirapplication techniques were studied.In this study,420microbical strains were separated from408samples, including rhizospheresoils, diseased plant debris and Sclerotias of Sclerotinia Sclerotiorum infected soybean plants byplate diluted incubation, trapping and endophyte separation from sclerotia methods, including227fungi,155bacteria and38actinomycetes.In door experiments were conducted and46strains with inhibition effect to S. Sclerotiorum,including31fungi,14bacteria and1actinomycetes, and3strains (M1M2, N1B9and G2) withgood inhibition effect to S. Sclerotiorum were selected to test the effect of control the disease infield pot experiment. The results showed that the control effect of M1M2to S.Sclerotiorum was76.2%and69.1%in door experiment and pot experiment, the control effect to S. Sclerotiorum ofN1B9was72.1%and44.4%, the control effect to S. Sclerotiorum of G2was67.9%and38.3%.The incubation conditions of M1M2were studied, which showed that the optimumtemperature of M1M2was30℃, the optimum pHwas4and the light needs to be kept for24h,while its mycelial growth and sporulation was highest.Results of fermentation test in lab showed that the optimum solid medium of M1M2wasconstituted of corn crushed grain: rice husk: wheat bran with rate of2:3:1and0.2g MgSO4and5ml water added every20g medium. The fermentation condition was20g liquid medium with7mLM1M2inoculation in250ml flask under28℃static culture, which get high amountsofsporulation.