Composite microbial agent for preventing and treating fruit tree replant disease and disease prevention method thereof

The invention belongs to the technical field of fruit tree disease prevention and treatment and discloses a composite microbial agent for preventing and treating a fruit tree replant disease and a disease prevention method thereof. The composite microbial agent and the disease prevention method solve fruit tree disease problems. The composite microbial agent is prepared by mixing a spore bacterium mixed agent and photoautotrophic bacterium, heterotrophic bacterium, fungus and saccharomycete liquid cultures according to a certain ratio. The disease prevention method comprises the following steps of clearing old trees, restoring soil, digging planting holes, preparing fertilizer soil and the composite microbial agent, backfilling the planting holes, and carrying out watering, covering and planting. The disease prevention method does not adopt any pesticide and chemical agent and realizes nontoxic, harmless, pollution-free and no-residual fruit tree replant disease treatment. The composite microbial agent can kill pathogenic bacteria and insect eggs in soil, increases soil organic matters, removes toxins secreted by roots, changes phosphor and potassium elements which cannot be absorbed and used by plants into available substances, improves soil fertility, creates a suitable environment for fruit tree growth and development, improves a fruit tree seedling survival rate, improves a fruit tree growth rate and a yield and overcomes fruit tree replant disease harm.