Kiwifruit brown spot disease is one of the main diseases of kiwifruit, which mainly damages leaves and branches, and is a serious leaf disease during the growth period of kiwifruit. The disease is a fungal disease, and the diseased part usually starts from the edge of the leaf. In the early stage, small water-soaked green spots appear on the edge of the leaf. Later, the lesion expands along the edge of the leaf, forming irregular large brown spots, and the periphery of the lesion is dark brown. The middle part is light in color, with many black dots scattered on it. Later, multiple diseased spots will merge with each other to form irregular large withered spots. In severe cases, a large number of diseased leaves will wither or fall off early, which will have a great impact on the yield and quality of kiwifruit.
Prevention methods are as follows:
① Strengthen field management, timely irrigate, drain, and pinch, improve field ventilation and light transmission conditions, spray foliar fertilizers to protect leaves, and improve leaf photosynthetic capacity.
② Increase the application of organic fertilizers to improve the soil structure and improve soil permeability; rational topdressing of organic compound fertilizers, combined with the supplement of medium and trace element fertilizers, can comprehensively improve tree vigor and tree resistance.
③ In the early stage of the disease, 500 times liquid of 50% carbendazim and thiophanate-methyl WP, 500 times liquid of 75% chlorothalonil wettable powder, 400-500 times liquid of 70% mancozeb can be used every 7-8 days Spray 1 time, and spray 2 to 3 times in total, which can effectively control the epidemic of diseases. Pay attention to prevention and control. In the case of high temperature, rainy, foggy and dewy, avoid using Bordeaux mixture, copper-containing preparations, and fungicides to avoid phytotoxicity. To avoid high-temperature periods, pesticides should be applied before 10:00 am and after 5:00 pm to ensure the safety of operators and crops.
