| Apple is the largest fruit in China,and the production of apple in Shandong ranks first in the country.Apple ring rot(Botryosphaeria dothidea)and apple leaf defoliation diseases(Alternaria mali)are common and serious diseases that damage the apple tree in Shandong Province.There is an important relationship between apple tree disease and tree nutrition.In this study,by investigating the Penglai and Qixia orchards in Yantai,fruit trees with different incidences of apple ringworm disease were sampled at four different stages in May,July,September,and November.Next,the shoots and leaves closest to the diseased trunk were collected without affecting the growth of fruit trees.And the contents of four elements of nitrogen(N),phosphorus(P),potassium(K),and manganese(Mn)in the shoots and leaves were determined.At the same time,the apple wheel on the fruit tree was collected.The incidence of striae disease was evaluated,and the differences in nutrient elements of fruit trees with different degrees of disease and the differences in nutrient status between healthy shoots on healthy plants and shoots on healthy plants were clarified using statistical methods such as one-way analysis of variance and LSD comparison.By investigating the Binzhou and Jinan orchards in Shandong Province,the fruit trees were sampled of the apple leaf defoliation diseases and brown blotch in the August,and the healthy leaves on the fruit trees infected with the diseased leaves were determined.The contents of five elements of nitrogen(N),phosphorus(P),potassium(K),manganese(Mn),and calcium(Ca)in healthy fruit trees clearly define the infection of two leaf parts.Differences in the nutritional status of fruit trees and fruit trees healthy victims.The results of the study are as follows:(1)By measuring the nutrient content of healthy shoots on plants infected with apple ring rot disease,and comparing with the corresponding degree of disease of the diseased plants,it can be concluded that Mn in shoots increases with the level of diseases of Apple ring rot disease.The content of elements showed an upward trend,the content of K elements showed a downward trend,and the N,P content had no obvious regularity with the degree of disease of Apple ring rot disease.(2)In orchards with similar ages and management levels,the K content of healthy shoots on plants infected with apple ring rot disease was lower than that of K on the shoots of healthy plants,and the Mn content was higher than that of healthy plants.The incidence of striae is related to the content of K and Mn.Appropriate potassium supplementation can reduce the occurrence of Apple ring rot disease and control the application of manganese-containing fertilizers,which can also serve to reduce apple ring rot disease.(3)By measuring the nutrient content of healthy leaves on plants infected with apple ring rot,and comparing with the corresponding degree of disease of diseased plants,it can be concluded that when the N content of healthy leaves on susceptible plants is at the standard value,the apple The incidence of apple ring rot disease is light,and when the element content is lower than the standard value,the disease severity is heavy.The manganese poisoning caused by the higher manganese content in the healthy leaves of the diseased plant is one of the reasons for the incidence of apple ring rotdisease.The increase in the content of Mn in leaves,the incidence of apple ring rot disease aggravated;with the apple disease level increased,the content of K elements in leaves showed a downward trend.(4)In the orchards with similar tree age and management level,the content of Ca in healthy leaves on plants infected with apple leaf spot defoliation was lower than that of healthy plants.By comparison with the standard value of leaf element content,the content of Ca in the healthy leaves of the diseased plant was lacking,while the content of Ca in the healthy plant was slightly lower than the standard value,indicating that the occurrence of the disease is related to the content of Ca,and the lack of Ca susceptibility to disease;The contents of K and P in the leaves of healthy plants were higher than those in the healthy leaves of the diseased plants.However,compared with the standard values of the content of leaf elements,the contents of K and P in the leaves of healthy plants and susceptible plants were still at the same level.The normal level indicates that the occurrence of deciduous disease is related to the K and P elements and lacks K and P susceptibility diseases.Appropriate calcium application of phosphorus and potassium can reduce the occurrence of apple leaf spot disease.(5)In the orchards with similar tree age and management level,the content of K in the healthy leaves of plants infected with brown blotch of apple was lower than that of healthy plants,which indicated that the occurrence of brown blotch in apple was related to the content of K,and it was lack of K susceptible..The content of N in healthy leaves of plants infected with brown blotch of apple was lower than that of healthy plants.By comparing with the standard values of the contents of leaf elements,the N content of healthy plants was slightly lower than the standard value,and the N content of diseased plants was The lack indicates that the occurrence of brown blotch disease in apples is related to the content of N elements and lack of N-susceptibility disease.Appropriate application of potassium fertilizer and nitrogen fertilizer can reduce the occurrence of apple brown blotch.In summary,the content of a large number of elements N,P,K has an important impact on the occurrence of apple tree diseases,the imbalance of middle and trace elements has an important impact on disease resistance of apple trees,N,P deficiency and apple ring pattern With regard to aggravation of the disease,high levels of Mn lead to aggravation of apple buffalo disease.The lack of K and Ca elements is associated with aggravation of apple leaf spot defoliation.The lack of K and N elements is associated with aggravation of apple brown blotch disease. |
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