Effect Of Combined Application Of Biocontrol Agents On Potato Verticillium Wilt Under Reduced Application Of Chemical Fertilizer And Pesticide

Verticillium wilt seriously restricts the development of potato industry.The pathogen can survive in soil for a long time in the form of dormant body,causing systematic infection,and the disease can occur throughout the growth period of potato.At the same time,there is a problem of excessive use of fertilizers and chemical pesticides for potato as an intensive crop.Therefore,biological control has become an ideal way to control diseases and reduce the use of pesticides and fertilizers.In this paper,two biocontrol agents were used in combination with chemical fertilizers and pesticides to further explore the effect of potato Verticillium wilt and potato yield,and to analyze the changes of soil microorganism,soil nutrient content and soil enzyme activity.1.The application of biocontrol agents can reduce the occurrence of potato Verticillium wilt,reduce the number of rhizosphere fungi,increase the number of bacteria and actinomycetes,and improve the soil enzyme activity and potato yield.2.With the same biocontrol agents,the control effect of reduced amount fertilization on potato Verticillium wilt was higher than that of excessive fertilization treatment,and it was more beneficial to reduce the number of rhizosphere fungi,increase the number of bacteria and actinomycetes,and improve the soil enzyme activity.The effect and net benefit of fertilizer treatment with bacillus subtilis S16 was better than that with Trichoderma PT29 and compound agent,with an increase rate of 45.65%?46.08%and a net benefit of 1134 yuan/667m2?1392 yuan/667m2.The effect of fertilizer treatment was the same as that with excessive fertilization,and the net benefit was higher.3.The quantity of rhizosphere bacteria and actinomycetes and soil enzyme activity under the same biocontrol agents treatment were higher than under the overdose treatment.The control effect of pesticide reduction combined with bacillus subtilis S16 on potato Verticillium wilt was better than that of Trichoderma PT29 and compound agent,and the control effect was 44.2%?51.7%,which could reach the level of overapplication.The effect and net benefit of increased production were better than that of overapplication,with the increase rate of 26.38%?34.43%,and the net benefit was 763 yuan/667m2?1201 yuan/667m2.