Bacillus Brevis Strain S6 WP Development And Control Effect Of Main Tomato Diseases

The main fungal diseases of tomato affect the yield and quality of tomato seriously.At present,the methods of preventing the main fungal diseases of tomato are mainly chemical control,but the long-term using of chemicals leaded to many problems such as low control effect,drug-resistance of the pathogens,excessive pesticide residue and pollution of the ecological environment.The biological control has many advantages example for highly effective,non-toxic,harmless,no pollution,no drug-resistance,protecting the environment.It has provided the safeguard for the sustainable development of agriculture,is an effective way of prevention and control of plant diseases.In this paper,Alternaria solani,Botrytis cinerea,Fulvia fulva,Phytophthora infestans on tomato were studied as object,wettability powder based on Bacillus brevies train S6 which was isolated and screened from the soil of tomato garden was developed,and the suitable type and proportion of the carrier,wetting agent,dispersant,protectant and stabilizer was clarified.The formula of Bacillus brevis strain S6 wettablility powder was 6%diatomaceous earth,7.2%polyethylene glycol,4.8%sodium lignosulfonate,0.1%dextrin,and 2%CMC-Na.The sperulate content of the wettable powder was 3.15×10~9 cfu/g,the suspension ratio was 81%,the wetting time was 23 s,and the thermal decomposition rate was 21.2%.By using the mycelial growth rate method,the indoor inhibitory effects of Bacillus brevis strain S6 wettablility powder and 12 other fungicides against tomato fungal diseases were determined.The results showed that 65%zeocin WP,70%methyl sulfide The bacillus wettable powder had good inhibitory effect to the pathogens of tomato fungal diseases,and the indoor inhibitory effect reached more than 90%.The 80%dimethomorph water dispersible granules had good effect to Fulvia fulva and Phytophthora infestans,and the effects were 94.43%and90.57%,respectively.10%polymyxin wettable powder has good effect on the pathogens of Botrytis cinerea and Fulvia fulva,and the effects were 87.86%and 87.29%respectively.The indoor inhibitory effect of Bacillus brevis strain S6 WP 400 times to Alternaria solani,Botrytis cinerea,Fulvia fulva,Phytophthora infestans was 89.87%,87.57%,44.43%,64.71%respectively.The inhibitory effects of 400 times liquid of Bacillus brevis strain S6 wettability powder to Alternaria solani、Botrytis cinerea、Phytophthora infestans were better,but its inhibitory effect to Fulvia fulva was not obvious.The field efficacy test was conducted by spray method.The results showed that the control effect of 50%isotricarb wettable powder on tomato early blight,gray mold,leaf mold,late blight were 91.68%,87.67%,80.34%,77.20%,respectively.70%Procezine wettable powder can control 91.70%,72.50%,54.59%,81.79%of Tomato Early Blight,Botrytis Cinerea,Leaf Blight,and Late Blight,respectively;65%zeosyn zinc wettable powder for tomato the control effects of early blight,gray mold,leaf mold,and late blight were 91.95%,90.46%,80.85%,81.84%,respectively;70%thiophanate-methyl wettable powder for tomato early blight,gray mold,and leaf mold the control efficacy of disease and late blight disease were 88.35%,90.55%,80.45%,64.33%,respectively;the control effect of 10%polymyxin wettability powder on tomato early blight,gray mold,leaf mold and late blight were 79.76%,66.35%,80.87%,65.44%,respectively;47%of Chunlei·Wang copper wettable powder had 89.77%,82.20%,79.94%and 57.83%of control efficacy against tomato early blight,gray mold,leaf mold,and late blight;80%of dimethomorph water dispersible granules had 90.27%,89.08%,78.25%,81.82%control effect on tomato early blight,gray mold,leaf mold and late blight.440g/L·chlorothalonil a fine suspension of tomato early blight,gray mold,leaf mold,late blight control effect were 87.97%,75.58%,65.01%,81.37%.In summary,the preferred pesticides are 50%isoprenil wettability powder,65%zeocin wettability powder,80%dimethomorph water dispersible granules,but the long-term use of chemical pesticides will produce crops.Drug resistance,so it is recommended to use biological pesticides for rotation prevention.Since 10%polymyxin wettable powder and 47%crayon·copper wettable powder are biopesticides that are widely used today,this experiment compares it with the control effect of Bacillus brevis strain S6 wettable powder and simultaneously observes Comparing the control effect of Bacillus brevis strain S6 wettable powder r with other 6 agents,it can be found that the wettable powder of Bacillus brevis strain S6 has very good control effect on tomato early blight and gray mold,and it has a good effect on tomato late blight.The control effect is general,and the control effect on tomato leaf mold is the worst.Bacillus brevis strain S6 wettable powder 400 times,800 times,and 1200 times 3 treatments,of which 86.31%,79.43%,and 71.49%of the control efficacy against tomato early blight,respectively,against Botrytis cinerea the control effects were84.82%,77.77%,and 71.31%,respectively.The control effects on tomato leaf mold were52.15%,53.99%,and 51.45%,respectively.The control effects on tomato late blight were68.64%,56.21%,and 54.46%,respectively.For tomato early blight,gray mold,and late blight,the wettable powder 400 times for Bacillus brevis is significantly higher than that for 800 times and 1200 times.It can be seen that the best effect is Bacillus brevis Strain S6 wettable powder400 times.The results showed that the wettable powder of Bacillus brevis strain S6 had a good preventive effect.The results of this study provided the theoretical basis for the prevention and control of the four main fungal diseases of tomato.