Apple spotted leaf disease control method
Harmful symptoms It mainly damages the leaves, especially the young leaves soon after spreading. In the initial stage of leaf infection, brown dots appear, with a diameter of about 2 to 3 mm, and then expanded to 5 to 6 mm. The reddish-brown side spots expand into irregular shapes. Some or all of them are off-white, and several small black spots are scattered on them. The lesions are broken or perforated. When the weather is wet, the dark green to dark brown mold layer can appear on both sides of the lesion. In the high temperature and rainy season, old leaf lesions expanded into irregular large spots up to several centimeters in length, and most or even the leaves of the leaves turned brown, causing the scorch to fall off. In the summer and autumn, the petiole of the summer and autumn will also show oval and dark depression spots, and the diseased leaves will fall off or break off from the petiole spot. Autumn shoots are seriously infected and there are dozens of lesions on one leaf. The tips of the leaves are dry and the leaves are twisted. The fruit can also be damaged. Black spots or scabs appear in young fruit, and black spots and browning appear in fruit near the ripening period. The law of incidence The pathogenic bacteria mainly overwintered in the lesions on the ground deciduous leaf, legless shoots, and shoot tip buds. After the apple tree germinated, the pathogenic bacteria on the deciduous lesions produced conidiospores, which spread with rain splashes until conidia were still produced on the leaves of the leaves in mid-June. In the middle and late May of May in the Bohai Bay area, lesions appeared on new shoots. Conidia began to form on new lesions from late May to early June. The disease entered a period of rapid growth. Diseases entered from early July to early August. During the peak period, the incidence decreased after August. The apple production area in the Loess Plateau in western China began to develop in the middle and early May. The onset and severity of onset are related to rainfall in spring and summer, relative air humidity, leaf age, and susceptibility of varieties. Before and after the apple tree leaves are inflated, if the rain is heavy and the air humidity is high, this time when the leaves are young, the onset is early, and the condition develops quickly. The highly susceptible varieties include the Marshals Department and the Beidou Department. The moderately susceptible species include Wang Lin, Fuji Department, Guoguang, Golden Delicious, and Jonah King. The mildly susceptible varieties include the World No. 1 and Tsugaru. Control methods Basic prevention and control measures: 1 Clear the garden timely after falling leaves, destroy the fallen leaves, and reduce the source of overwintering. 2 Strengthen orchard management, increase tree vigor, and improve disease resistance of fruit trees. Pollution-free food orchard control technology: 1 Before the onset spray 70% Prosin Zinc (Antaisheng) WP 600 times, 80% Mancozeb (Dasheng M-45) WP 1000 times, 68% 代森Manganese zinc (Easy Protection) 1200 times and so on. 1 At the beginning of the disease, use 43% tebuconazole (Holico) suspension 3000 times liquid, you can also use difenoconazole (Shigao) 10% water dispersion granules 1500 ~ 2000 times, myclobutanil + Manganese zinc (62% Xiansheng WP) 600 times, 40% myclobutanil (Shansheng) WP 8000 times and so on. Green food (Grade A) orchard control techniques: (1) spray 10% polymycin wettable powder 1000 ~ 1500 times before the onset of the disease, or 70% Propylene Zinc (Aetnax) wettable powder 600 times. (2) Spray 50% iprodione (promethine) wettable powder 1000 to 1500 times, or 43% tebuconazole (Holiker) suspension 3000 times at the beginning of the disease. Organic food, green food (AA grade) Orchard control technology: Before and after the onset of the disease, spray 10% polymyxin WP to 1000~1500 times 1~2 times, and later spray Bordeaux multi-solution 1~2 times. Puffed Corn Flour,Emulsifier Puffed Corn Flour,Hot Puffed Corn Flour,Feed Puffed Corn Flour Jiangsu Chenwei Biology and Technology Co. LTD , https://www.cwsoybean.com