Timely prevention of common diseases in autumn

Powdery mildew to melon, rose, dahlia, wolfberry, balsam, zinnia, euonymus, boxwood and other flowers suffered the most serious. The injured parts are scattered first

The small white spots of the cloth gradually spread and spread, and the development speed is very fast. Under suitable conditions, the disease spots can be covered with the whole leaves in 7~10 days, and the surface of the leaves is covered with a layer of white powder, just like frost. When it is serious, the leaves wither and fall early. Plants lose photosynthesis, resulting in fewer flowers, small color pale, and some even do not bloom. The disease in stems and leaves too dense, sultry weather, poor ventilation and light transmission, soil moisture conditions, rapid onset, serious harm. Control methods: 1, enhance ventilation and light transmission conditions; increase phosphorus, potassium fertilizer, avoid partial application of nitrogen fertilizer, watering can not be excessive, more can not let the basin soil water, of course, can not lack water; and to timely remove sick leaves, sick buds, pull out sick plants, concentrated burning. 2. Chemical control. At the beginning of the disease, some flowers can spray 1:1:140 equivalent Bordeaux mixture, or 25% triadimefon 1500 times solution, 70% methyl thiophane 1200 times solution, 50% Tuijunte 1500 times solution. The above agents can be used alternately to improve the control effect. When seriously ill, it is necessary to spray once every 7 days, and spray 2 to 3 times continuously. Brown spot disease is also mainly harmful to leaves. Brown spots appeared on the leaves at the beginning of the disease, and then the spots gradually expanded into large spots. The spots were irregular due to the limitation of vein. There is a faded halo on the periphery, the edge is reddish-brown, the center is gray-white, black dots (conidia) are produced in the late disease spots, the leaves of the damaged plants are easy to fall off, and the heavy ones do not have a leaf. The whole plant gradually dies from bottom to top. To azalea, narcissus, jasmine, clove, osmanthus, flowering crabapple, heather, lotus and other flowers suffered heavier. Control methods: 1. Cut off diseased branches and leaves in time, burn them intensively, and reduce re-infection bacteria. 2. Chemical control. After the disease, spray 80% Dijundan 500 times solution, 65% Dezeb 800 times solution, 12.5% Rapoli wettable powder 1000 times solution, 70% thiophanate methyl 1200 times solution every 7~10 days, spray 2-3 times continuously. Flower rot mainly damages flowers, buds and fruits, but also leaves. After the leaves were damaged, small reddish brown spots appeared, which gradually expanded later, resulting in a large number of gray mold objects in the diseased part. When the buds just appeared, they could be infected and rotted, and the diseased flowers were brown and withered. The disease was easy to occur under the conditions of autumn rain, humidity and fog. The disease is harmful to dahlia, cockscomb, rose, crape myrtle, zinnia, anemone and pomegranate. Prevention and control methods: 1, continuous rainy weather, to take rainproof measures, do not let buds, flowers by rain attack. At ordinary times, cultivation management should be strengthened, phosphorus and potassium fertilizer should be applied, pruning should be reasonable, and ventilation and light transmission should be enhanced. 2. Chemical control. Spraying 3~5 ℃ Bome sulfur mixture before disease onset can play a protective and preventive role. At the beginning of the disease, 5% Tian 'an water solution 500 times, 50% Tuijunte WP 1500 times and 75% Chlorothalonil 1000 times can be sprayed. When seriously ill, spray once every 7-10 days for 2 - 3 times of continuous prevention and control.