Studies On Control Effect Of Integration Biocontrol Agents Combined With Fungicide Against Fusarium Wilt And Verticillium Wilt

In order to build up integration strains with superior growth promoting effect and enhanced disease suppression, the biological control efficacy of solid agents of strain Fo47 mixture with actinomycetes strains 153, SC11, PR and F46 and carbendazim with low concentration toward fusarium wilt disease of watermelon and cotton and verticillium wilt of eggplant and the effect on growth and development of watermelon, cotton and eggplant was investigated in pot experiments, aiming to provide a theoretical basis for practical application with biocontrol agents.The resistant ability of 5 biocontrol strains to carbendazim, agricultural antibiotic 120 and triophanate-methyl was detected. The results showed different resistance to the fungicides or antibiotics. Strain Fo47 and strain PR showed low resistance, the critical point of strain Fo47 to carbendazim was only 2μg.mL-1. High resistance of strain 153, SC11 and F46 to the fungicides and antibiotics was detected. Strain SC11 was not sensitive to carbendazim, which could grow even with the concentration of 1000μg.mL-1 of carbendazim.The substrate of solid fermentation of the 5 biocontrol strains was defined by the selection of solid fermentation substrate. The dynamic variation of viable propagule of biocontrol strains was tested, the results showed that viable count of strain Fo47 and the 4 actinomycetes strains in solid state showed an overall declining trend over time, which were stored at room temperature. Due to high initial viable count, the effect on the activity of biocontrol agents was not obvious, which still kept relatively high amount of live propagule. The viable count of strain Fo47 in soil with the integration agents and with carbendazim treatment was detected. Viable count of strain Fo47 in integration agents showed upward trend in the first 40 days, and began to decrease at the 50 days. With the carbendazim in soil, the viable propagule of strain Fo47 was lower, at the level of 104-105cfu/g after inoculation 50 days.Inhibition effect on target pathogens by biocontrol agents with canbendazim showed significant differences. Strain SC11 had significant inhibiting effect on Fusarium oxysporum and Verticillium dahliae in vitro, inhibiting effect of biocontrol strains combined with fungicide on the target pathology was better, higher than the application of single strain. In pot experiment, the control effcet of fusarium wilt and verticilium wilt by strain Fo47 and integration agents with Carbendazim was significant, the treatments with the carbendazim showed bettet biocontrol effect than the treatments withnot carbendazim. Control effects on fusarium wilt disease of watermelon and cotton and verticillium wilt of eggplant with C4 and carbendazim were significant, reached 59.91%, 71.31% and 58.21%, respectively, with the best control effect on the fusarium wilt of cotton. C3 with carbendazim also showed high biocontrol effect on the 3 kind of plant disease, which reached more than 50%, respectively, with the best contro effect on the verticillium wilt of eggplant.Colonisation rate of strain Fo47 in plant tissue of watermelon, cotton and eggplant with different treatments was significantly different. The colonisation ability of strain Fo47 in the integration agents was better than that in the treatments with carbendazim. Colonization rate of strain Fo47 in C4 in the root of cotton and eggplant both achieved 100%, and colonization rate of Fo47 in C3 in the root and stem of eggplant also reached 100%. In single strain treatment, colonization rate of Fo47 reached 80% or more in the three kinds of plant root. Overall, colonization rate of strain Fo47 in roots of the three kinds of plant was highest, the lowest in leaf. Besides, the colonization rate in cotton was higher than that in watermelon and eggplant.Growth promoting effect of seedings by solid integration agents and carbendazim was tested. Handled by different combined agents, the physiological indicators of three kinds of seedings were different significantly with control, most of treatments showed different degrees of growth promoting effects. The effect on the fresh weight and dry weight of the watermelon, cotton and eggplant was the most significant. After the treatment of integration agents and carbendazim, the seeding was healthy and strong, with dense green leaf, robust stem and developed root.The viable propagule, growth speed and the antibiotic activity of biocontrol agents could enhanced via the solid fermentation methods, and the solid biocontrol agents was stable, suitable for keeping a long time.