Study On The Occurrence Of Apple Tree Valsa Canker And Biological And Chemical Control In Shuanghe City,Xinjiang

Apple tree Valsa canke is a branch and trunk disease with latent infestation characteristics that occurs in all major apple producing areas in China.The occurrence of apple tree Valsa canke is an important basis for disease prevention and control,and there is a lack of research on apple tree Valsa canke in Shuanghe City,Xinjiang.In this study,we conducted a survey on the incidence of apple tree Valsa canke in the honeycrisp apple demonstration orchard of 81 Mission in Shuanghe City,Xinjiang,and also studied the extent of apple tree rot and the content of nitrogen,phosphorus and potassium elements in apple tree branches and leaves,and sprayed three kinds of The results of the study are as follows:(1)From April to May 2021,the peak of new spots in the honeycrisp apple demonstration orchard of Xinjiang Shuanghe City Mission 81,with a monthly average of 99.5 new spots,accounting for 91.28% of the new spots during the whole growing period,and a gradual decrease of new spots after June.the spots expanded faster from April to June,with a monthly average expansion of 0.67 cm accounting for 77.14% of the expansion during the whole growing period.The highest incidence of 38.22% was found in apple trees at pruning compared to branching,main stem,side branches and mechanical damage.(2)The elemental contents of nitrogen,phosphorus and potassium in apple tree rots at the early(late)stage of disease onset were 0.81%,0.07% and 1.104%(1.51%,0.11% and 0.182%)in branches and 3.57%,0.12% and 5.04%(2.72%,0.16% and 3.7%)in leaves,respectively.The degree of apple tree rot incidence was positively correlated with the content of nitrogen and phosphorus elements in branches and significantly negatively correlated with the content of potassium elements,and the degree of disease incidence was significantly positively correlated with the content of phosphorus elements in leaves and negatively correlated with the content of potassium elements.(3)Amino-oligosaccharide sprayed on apple trees at the young fruiting stage and fruit expansion stage can induce host resistance,and the effectiveness of prevention against rots is 88.89% and 91.67% respectively;chemical agents with additives can help to improve the effectiveness of prevention,tebuconazole 200 times of solution + Turbinate 100 times of solution and tebuconazole 200 times of solution + Turbinate 100 times of solution,the effectiveness of prevention against rots in both treatments is 87.5%;chemical agents The highest efficacy of tebuconazole 200 x and Bacillus subtilis 200 x 5:1 treatment was 81.2%,the better efficacy of Bacillus subtilis 200 x and daidzeinium 200 x 1:2 treatment was 75.2%,and the lowest efficacy of tebuconazole 200 x and Bacillus subtilis 200 x 1:5 treatment was 69.2%.