Research On The Technology For The Prevention And Control Of Two Soil-borne Diseases Of Tomato By Bacillus And Chemical Agents

In recent years,soil-borne diseases of tomato,which has been occurred frequently,has restricted the development of tomato industry.In this paper,based on Bacillus spp.and chemical agents,two soil-borned diseases of tomato were studied to facilitate analysis of the control effects of these tehniques.In addition,the quantitative change of Bacillus spp.in soil were monitored by RT-qPCR.The control technologies of two soil-borned diseases of tomato were established based on the seedling raising technology of paper bowl.1、Screening and identification of biocontrol bacter.115 strains of biocontrol bacterial were isolated from diseased samples and soil.Bacillus velezensis and Bacillus subtilis were used as biocontrol bacter.2、The RT-qPCR detection system of Bacillus spp.was established.The sensitivity of the detection system was 1000 times than that of conventional PCR.Aanlysis of the colonization of Bacillus spp.in soil was specific,rapid and quantitative.3、The optimum dosage of Bacillus spp for controlling tomato root rot was determined.Bacillus velezensis with a concentration of 1×10⁸ cfu·mL^-11 was treated with 10 mL/plant root irrigation,which had the best control effect on tomato root rot（60.39%）,and the strain had the ability to produce indoleacetic acid.Using the established RT-qPCR detection system,the strain was detected to reach the maximum bacterial count at the 5th day after the colonized,the same time,the pepper Phytophthora capsici Leonian quantity reached the minimum,the copy number were 3.87×10¹⁶copys·μL^-1、1.02×10¹44 copys·μL^-1,and then the Bacillus velezensis quantity gradually decreased,reached the minimum bacterial count at the 30th day,the copy number was 1.14×10¹33 copys·μL^-1.4、The optimum compound dosage of biocontrol bacteria and chemical agents was determined.The application of 10 mL/strain of Bacillus velezensis with concentration of 1×10⁸ cfu·mL^-11 and pyrazole ester 0.25 mg·kg^-11 had the best control effect on tomato root rot,and the control effect was 61.9%.Similarly,the application of 5mL/strain of Bacillus subtilis suspension with a concentration of 1×10⁸cfu·mL^-11 combined with aniline 0.3 mg·kg^-11 had the best inhibitory effect on tomato stem and basal rot bacteria,and the inhibitory rate was 68.7%.5、The control effect of Bacillus velezensis and pyrazole ester on tomato root rot was determined to be 87.5%by using the technology of setting paper pot seedling cultivation.Similarly,the control effect of Bacillus subtilis and aniline was 55.25%.In this study,the optimal formula of biocontrol bacteria and chemical agents was obtained through laboratory measurement and pot experiment,and the technology of setting paper pot seedling cultivation,the fixed-point prevention and control effect of tomato root rot and stem base rot in the field was defined,providing theoretical basis and technical support for its application in production.