Integrated control of loquat gray leaf spot

Loquat gray leaf spot is also known as "wheel spot". It is the most important disease of loquat. Encroach on branches, leaves, flowers, fruits. There are two types of acute and chronic types: chronic disease spots on the leaves, initially light brown round spots, and then connected into irregular large spots, scattered small black spots. Twig disease, first by waterlogged small brown spots, and then into black-brown spots, branches withered. The big branch is sick, after the disease part blackens, has the reddish brown halo spot, the branch withered skin warps. The flower ear is infected, and the branch axis becomes yellowish brown and withered; the petals have oil-stained dots at the beginning, and then brown and wither. Mature fruit infected, the fruit surface has a large area of brown rot, after obvious depression, scattered with small black spots. Acute disease spot, mainly make the edge or tip of the leaf has a large scorch, the formation of a large number of fallen leaves. Prevention and treatment methods: (1) remove fallen leaves and reduce the source of disease. Avoid too high humidity in the shed; (2) strengthen fertilizer cultivation, do a good job in pruning, timely drainage or drought resistance, enhance tree potential, enhance disease resistance. (3) pay attention to the use of pesticides, that is, it is more effective to use different pesticides in different periods. ① Bordeaux solution and stone sulfur mixture are excellent pesticides for the control of loquat gray spot. Use 0.3-0.5% Bordeaux solution and Baume 0.3-0.5 degree stone-sulfur mixture. After use, it can not only prevent disease, but also supplement copper and calcium to loquat. However, the two drugs have an effect on flowers and young fruits. Therefore, it can only be used after fruit picking and before budding. ② 80% essential wettable powder contains calcium cupric sulfate, sprayed 400m600 times, and Bordeaux solution and stone sulfur mixture have both disease prevention and calcium supplement effect. But it can only be used after fruit harvest and before budding. ③ 70% mancozeb 600x solution, or 80% Dasheng MMI 45600 fold solution, are some preventive pesticides. It should be used before or at the beginning of sprouting to have the effect of disease prevention. After ④ sprouting, some pesticides with preventive, protective and therapeutic effects should be used, such as: 50% carbendazim wettable powder 800x solution; or 70% methyl topiramate 600x solution; or 40% new star (Fuxing) 8000 fold solution; or 25% metalaxyl (pyrethromycin) 500g 800 fold solution; or 75% chlorothalonil 600g 800 fold solution.