Identification Of Antagonistic Strains,Effects Of Indoor Inhibition And Field Control To Major Tomato Diseases

In this paper,the main diseases of tomato were early blight,gray mold,leaf mold and late blight as target diseases,and the morphological characteristics,physiological and biochemical and molecular biological identification of strains A8 and A37 with high antibacterial effect were identified.The nutrient conditions and culture environment required by the two strains,through indoor bacteriostasis and field control tests,showed that the fermentation broth of antagonistic strains A8 and A37 had better control potential for the main diseases of the above tomato.The specific results of the full text study are summarized as follows:1.Morphological characteristics and physiological and biochemical measurements,the morphological characteristics and physiological and biochemical properties of strains A8 and A37 were consistent with Bacillus Cohn,combined with 16 S rDNA sequence analysis,and finally determined that strains A8 and A37 were Belize spores.Bacillus velezensis.2.The growth curves of antagonistic strains A8 and A37 indicated that the bacterial culture was continuously cultured for 14-18 h as the optimal culture time of the seed solution.Through the single factor test and orthogonal test optimization of carbon source,nitrogen source,inorganic salt and other factors,the suitable medium components of strains A8 and A37 are glucose(Glucose)2%,yeast extract fermentation(YEF)0.5%.,KCl 0.75%,distilled water 1L.The optimal culture conditions for strains A8 and A37 were as follows: temperature 29 ° C,time 72-84 h,pH value natural pH(pH=7.23),rotation speed 210 r/min,inoculum volume 3%,250 mL standard solvent The amount of liquid in the bottle is 100 mL.3.The effects of different concentrations of fermentation broth of strains A8 and A37 on the inhibition rate of mycelial and spore germination of four pathogens of tomato were analyzed.The results showed that the four pathogens were not diluted when the fermentation broth of strain A8 and A37 was not diluted.The inhibitory effect of mycelium and spore germination was the most obvious.The inhibition rate of mycelial growth was 95.44% and 94.56%,respectively.The highest inhibition rate for spore germination was 98.6% and 98.77%,respectively.The difference in performance is not significant.As the dilution factor continues to increase,the inhibition rate is also declining.The tomato early blight and the gray mold pathogen mycelium after being inhibited by the antagonistic strain A8 fermentation broth have obvious deformities.4.The field control effect of strain A8 and A37 fermentation broth on tomato early blight and tomato leaf mold was carried out by spray method.The results showed that the control solution of the fermentation broth of antagonistic bacterial strains A8 and A37 was similar to the control effect of the chemical agent 70% chlorothalonil 1000 times liquid and quick kiling 2000 times liquid,and the difference was 5%.Not significant,the inhibition rate of tomato early blight was 79.17%,80.16%,and the inhibition rate to tomato leaf mold was 77.14% and 76.25%,respectively.In the process of 50,100,and 150 times treatment of the fermentation broth,the control effect is gradually decreased as the dilution factor is increased.