Control Function Of Three Kinds Of Biocontrol Strains For Withered Verticillium Wilt In The Field

Cotton fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum and eggplantverticillum wilt caused by Verticillium dahlia are devastating vascular soil-borne diseases,the pathogens which have a very high resistance are soil inhabitant fungi, chemical pesticidesare difficult to effective control on it. Biological control has stabilize control effect, longduration and environment-friendly for the favoured by people gradually. To get the biocontrolagents which can effectively control the fusarium wilt and verticillium wilt under fieldconditions, we selected the strain SC11, the strain153and the strain Fo47which all havestrong inhibitiory effect to the Fusarium oxysporum and Verticillium dahlia, throughinvestigation its affinity, shelf life, influence on crop growth, diseases control ability andsurvival ability under field conditions, provide an important theoretical basis for biocontrolagents’ commercial development and using in the actual practice of agricultural production.Through propagation of the selected biocontrol agents, determine the affinity and theshelf life, The biocontrol agents powder initial viable cells increase by two orders ofmagnitude than the quantity of the corresponding fermentation broth, the initial quantity ofviable cells of strain153powder up to3.23×10⁸cfu g^-1; each selected biocontrol agentswith good affinity, the strain153has which can be arbitrary mixed with the other two strains;All selected biocontrol agents powder can be well preserved at room temperature, biocontrolagents powder viable count remained stable within1year.Through the growth impact research of biocontrol agents in cotton and six-leaf eggplantunder field conditions, the selected biocontrol agents have a role in promoting the growth ofcrops, fermentation broth is more effect than powder in promoting the growth of crops, thefermentation broth of strain Fo47make an increase of68.66%of cotton lint yield, The strain153has the obvious effect in growth promoting,84.80%seed cotton yield can be improved.Throgh the ongoing view of the biocontrol agents inflence on cotton Fusarium wilt andeggplant Verticillum wilt disease index, the selected biocontrol agents have stable controlfunction on cotton Fusarium wilt and eggplant Verticillum wilt under field conditions, Crop disease index continues to reduce, the final ability of the disease control is better than the50%carbendazim controlled. The field disease control effect of the strain153is better thanthe strain SC11and the strain Fo47, cotton Fusarium wilt and eggplant Verticillum wiltdisease index fell to38.2and23.5respectively. In practical agricultural production, we cancombine biocontrol agents with a certain dose of the chemical pesticides for sustained andefficient control of crop diseases.Through determine constantly changing of live concentration of continuous change ofbiocontrol agents survival in crops rhizosphere and organization under field conditions, Strain153can stable colonization in rhizosphere and organization of cotton and six-leaf eggplant,which concentration of colonization keep dynamic balance, concentration of colonization inthe cotton organization is as high as105cfu·g^-1, mean while, the strain SC11and the strainFo47could only long term colonize in crop rhizosphere soil; Under field conditions, Thecolonization concentration of biocontrol agents has been in a state of dynamic equilibrium,which Temperature, humidity and other weather factors have great impact on colonizationconcentration of biocontrol agents; The biocontrol agents colonization ability due to differentbiocontrol agents and plant species and plant tissue differentiation exists significantdifferences.Studies show that selected biocontrol agents powder exihibit good shelf life, the role ofcrop growth promoting and the ability of disease controlling are obviously in the field, part ofbiocontrol agents with a strong field viability, which provide an important theoretical basisfor biocontrol agents’ commercial development and using in the actual practice ofagricultural production.