Evaluation of Control Effect by Bacillus subtilis on the Damping-off and Verticillium wilt of Cotton

【Objective】 To identify the control effects of Bacillus subtilis on cotton damping-off and Verticillium wilt, and the effects on yield and fiber quality. 【Methods】 Three wet table powders with 1 billion live spores / g, 1.5 billion live spores / g and 3 billion live spores / g were set up through the field experiment, and the seeds were treated before sowing at 1:10 according to the seed ratio. The control effects of different treatments on damping-off and Verticillium wilt as well as their effects on yield and fiber quality were evaluated. 【Results】 The three treatments could reduce the diseased plant rate, disease index and seedling mortality rate of damping-off, 1.5 billion live spores / g had the best control effect, which was 44.31%. 1.5 billion and 3 billion live spores / g treatments had significant control effects on Verticillium wilt, and the diseased plant rate and disease index were significantly lower than that of the control. Among them, the control effect of 1.5 billion live spores / g treatment was as high as 70.71%. The seed cotton yield and boll weight of the three treatments were increased, and the seed cotton yield of 1.5 billion and 3 billion live spores / g treatments increased by 20.1% and 24.3% respectively; and there was no significant effect on lint percentage, seed index, boll number per plant and fiber quality index. 【Conclusion】 Bacillus subtilis seed dressing treatment can reduce the seedling death rate, the diseased plant rate and disease index, and also increase boll weight and seed cotton yield and has no adverse effect on the fiber quality of cotton. Among them, 1.5 billion live spores per gram treatment have the most significant control effect and can significantly increase the yield, so it can be recommended.