How to prevent and cure powdery mildew of rose
Powdery mildew mainly harms leaves, tender shoots, buds and pedicels of rose. After the young leaves are infected, the leaves shrink, curl into deformities, and sometimes become purplish red. The old leaf is susceptible, the leaf surface appears nearly round, water stain-like chlorotic macula, seriously damaged, the leaf withered and fell off. The damaged parts of tender shoots and pedicels were slightly enlarged and the top of them bent to the ground. After infection, the flower bud can not open or the flower posture is deformed, and the surface of the damaged part is evenly covered with white powder layer. Powdery mildew occurred more frequently in spring (May, June) and autumn (September and October), which was the peak of the disease. If rose is cultivated in greenhouse, powdery mildew can occur every year. Powdery mildew can be harmed when the room temperature is above 5 ℃. The disease is more serious when the temperature is high, the humidity is high, the heat is muggy and the ventilation is poor.
Prevention and control measures 1. The application of nitrogen fertilizer should not be too much, and the amount of calcium and potassium fertilizer should be increased appropriately to make the plant grow strong and enhance the ability of disease resistance. two。 Spray 3-4 Baumedo stone sulfur mixture before germination to eliminate overwintering bacteria. 3. At the initial stage of the disease, 15% powder was sprayed with 1000 times of carbendazim or 50% carbendazim.
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Control of powdery mildew of cut rose
Powdery mildew is one of the most important diseases of rose, which harms leaves, tender shoots, buds and pedicels. The control methods are as follows: strengthening cultivation management and timely removal of the disease; pruning in time to improve ventilation and light transmission conditions; nitrogen fertilizer should not be too much, it is necessary to increase the application of phosphorus and potassium fertilizer. To prevent and cure the disease during the growing period, 15% fenvalerate wettable powder can be sprayed with 2000-4000 times of metoprolol wettable powder or 1000 times of 50% metoprolol wettable powder, 1000 times of 50% benzoate wettable powder, and 800 times of 30% fluconazole.
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Identification and control of rose powdery mildew
Symptoms: germs infect leaves, floral organs, tender shoots of rose, etc. In early spring, the leaves of the diseased buds are covered with white powder on both sides. The leaves shrunk and became thicker, and then gradually dried up and died, which became the source of primary infection. During the growing season, the leaves were infected, first appeared small white powder spots, then gradually expanded into round or irregular shaped white powder spots, and in severe cases, the white powder spots were connected to each other. When the young shoots and petioles fell ill, the disease spots increased slightly and the internodes shortened. The buds are covered with powdery layer, withered and withered. A lightly diseased bud
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