| Watermelon wilt disease is one of the serious diseases of the watermelon planting industry faces in our country, its pathogenesis wide area, speed, greatly influenced of the yield of watermelon, has great harm to economic benefits of the broad growers and the watermelon planting industry in our country, the effective prevention and control for watermelon fusarium wilt has become a problem to be solved in watermelon production. The traditional chemical pesticide control due to its environmental pollution, pesticide residues and the resistance caused by plant diseases and insect pests, is already can not adapt to the requirement of green products, ecological agriculture, and the sustainable development of agriculture. As a kind of widely used trichoderma bio-control strains, because of wide existing, strong adaptability, and the advantages of broad spectrum efficiency, is recognized as the most potential bio-control bacteria.In this paper, a preliminary study on the mechanism and biocontrol effect of control Watermelon Fusarium Wilt by the Trichoderma harzianum T2-16, the results are as follows:1. T. harzianum T2-16 has good control effect to watermelon wilt:pot experiments showed that treat watermelon seeds and seedlings with Trichoderma by various treatment methods can different reduce the levels of watermelon Fusarium wilt, the best control effect reached a significant 60.00% by the treat method of Trichoderma base material. Field application results showed that after trichoderma viride treatment the watermelon wilt disease incidence and death rate were significantly lower than ck processing, the prevention and control effect was 53.11%。2. Tharzianum T2-16 fermentation broth can improve watermelon seed germination potential, and promote the growth, increase production:germination test results showed that after T2-16 spore suspension soaking, early spring ruby watermelon seed germination and seedling growth have certain role, showing the germination rate, germination index and vigor index has a different degree of increase, and Trichoderma treatment can improve watermelon yield by 14.19%.3. T.harzianum T2-16 can induce watermelon resistance to Fusarium oxysporum: from dual culture and microscopic observation results can be seen T. harzianum can inhibit the growth of Fusarium oxysporum, inhibition rate reached 67.21%, and Trichoderma mycelium can mycoparasite to Fusarium mycelium, suggesting that the role of competition and parasitism is the main antagonistic mechanism of Trichoderma harzianum T2-16 to Fusarium oxysporum; By detecting the enzyme activity changes of phenylalanine ammonia solution (PAL), peroxidase (POD), catalase (CAT) and polyphenol oxidase (PPO) associated with induction of plant disease resistance after application of trichoderma in the watermelon plant found that the several defense enzyme activity are different degrees of increase in the plant after trichoderma processed, show that trichoderma processing can stimulate the watermelon plant to produce higher levels of defense enzyme activity against pathogenic bacteria infection.4. T.harzianum T2-16 can impact on watermelon rhizosphere soil microbial populations:in addition to the bacterial growth rate higher than the control treatment, fungi, actinomycetes, nitrogen-fixing bacteria and ammonia bacterial growth rate of the T.harzianum treat are significantly lower than the control treatment. Applied that because of harzianum competition for pathogens, parasitic and antagonism changed watermelon roots soil microorganisms living environment, thus inhibiting the growth of roots in the soil watermelon culturable microorganisms.5. T. harzianum T2-16 can colonize in watermelon plants, and thus play its disease prevention and promote growth effect:the colonization results show that: Trichoderma harzianum in watermelon can successfully colonize in the watermelon body, thereby forming a symbiosis with the watermelon plants, inhibit the growth of Fusarium oxysporum, boosting the watermelon plants to resistance to Fusarium disease. |
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