The Endemic Factors Of Tomato Bacterial Wilt In Soilless Culture System And Prevention Approache By Micro-ecological Environment

Sufficient pathogen, susceptible host and favourable environmental conditions,which are necessary to the outbreaking of the plant disease. Generally speaking, theways of controlling the disease contain decreasing the pathogen population,culturing resistant plant and creating unfavourable environmental conditions to theoutbreaking of the plant disease. In the present experiment, cultivar "Shengnv"which is highly susceptible to Ralstonia solanacearum was choosing asexperimental materials. The numericalthreshold of infection and infectionprobabability of the Ralstonia solanacearum in hydroponic system werediscovered; Effects of non-biologic and biologic factors of substrates to tomatobacterial wilt was discovered; effects of adding slow-release organic fertilizer (SROF)to substrates on control of tomato bacterial wilt was discovered. Main researchresults were as follows:The disease index of tomato bacterial wilt and infection probabability of theRalstonia solanacearum in hydroponic system increased as the inocuulum densityincreasing; The numericalt hreshold of infection below 3×10² cfu·mL^-1;Temperature affecting the disease index greatly, the disease index declined when thetemperature fell. The higher infection probabability of the Ralstonia solanacearumas the inocuulum density increasing indicated that there are synergetic effect andenganced infection among Ralstonia solanacearum.We positioned 6 compound substrates into 3 groups according to the diseaseindex, mushroom residue and mushroom residue:perlite=1:1(â…¤:â…¤, the same as below)were positioned in the group highly susceptible to this strain. Perlite:peatmoss=1:1,sand and mushroom residue: vermiculite=1:1 were positioned in the group lowersusceptible to this strain. The vermiculite was positioned in the hardly susceptiblegroup. The tomato bacterial wilt more serious as the value of airation porosity vswater-retaining porosity increasing. Microbes in surrounding and srhizosphericsubstrates suppressed the tomato bacterial wilt; The lower pH value would cause thedisease more serious.Adding SROF to the Mushroom residue and vermiculite could promote theplant growth, increase chlorophyll,soluble sugar and soluble protein obviously;increased the number of microbes in surrounding and srhizospheric substrates and decreasedthe R/S; increased the SOD,POD,CAT and PAL activity of the leaves of tomatoseedlings after injecting Ralstonia salanacearum suspension(3×10⁸ cfu·mL^-1)to tomatostems.; decreased the disease incidence and disease index after pouring Ralstoniasalanacearum suspension(3×10⁸ cfu·mL^-1) to substrates.