Prevention of early apple deciduous disease

The weather is rainy and irritating, which is very conducive to the occurrence of early defoliation of apples such as apple spotted leaf disease and brown spot disease, and the prevention and control of early defoliation is focused on prevention. Early prevention is more effective, and the effect is not good after the onset of the disease. Agricultural measures should be done after the rain in the orchard. It is necessary to pay attention to timely planning, reduce the humidity and improve the permeability of the root system. If the surface humidity is too large, it can also be applied to the ground by the ash, which can absorb moisture and reduce the occurrence of diseases. The conditional orchard should try to plant grass, cover, and do the drainage work of the orchard, so that the rain stops the field and reduces the humidity. Reasonable pruning, pay attention to improve the ventilation and light conditions of the orchard and canopy, and strictly prohibit excessive blind stripping and circumcision, thus maintaining a robust tree. It is very important for the first spraying of pharmacy to control the spotted deciduous disease in the spring shoot period (from late April to late May) and the autumn shoot period (from late June to mid-July); brown spot disease can occur from June to August. From July to August, the peak incidence period. Practice has proved that it is very important to prevent the initial infection by spraying. Generally, from April 20, 7 to 10 days after flowering to fruit ripening (November), it is necessary to spray once every 10 to 15 days to protect the leaves and prevent infection. Spraying must be closely related to the rainfall situation, adhere to the idea of ​​“spraying after the rain”, and follow the principle of spraying more rain, less rain, less rain, and no rain. Spraying in the rainy season is the key epidemic disease of wind and rain. It is rainy from July to August, and the disease is serious. The rain is slow from July to August. The disease is difficult to occur seriously. On the basis of the first spraying, the fruit farmers should pay close attention to the rainfall from July to August, spray in time, and control the epidemic. . In general years, 7 to 8 servings should be sprayed 2 to 4 times. Improve the quality of spray and the quality of spray, which has a great impact on the control effect. Spraying must be meticulous and thoughtful, and the branches should not leak, especially the internal branches of the canopy should be sprayed, so that the leaves, the back and the fruit should be evenly coated. The brown spot pathogen mainly invades from the back of the leaf, and the spray should focus on the even side of the leaf. At the same time, the higher the degree of atomization of the liquid, the better the control effect. There are many effective agents for the correct use of pesticides to prevent early defoliation. It is recommended to use: 80% mancozeb WP 800 times or 43% tebuconazole suspension 3000~4000 times, 10% difenoconazole. Water-dispersible granules 4000~5000 times liquid, 3% polymycin-resistant wettable powder 500~600 times liquid, etc. If the diseased leaf rate exceeds 3%, it is necessary to use the weather-stricken water to wash the 77% Bordeaux mixture 800 times liquid before the rain. (Qin Fei)