MySheen

How to prevent and cure powdery mildew of rose

Published: 2024-12-23 Author: mysheen
Last Updated: 2024/12/23, 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. In open field cultivated rose, powdery mildew occurred more frequently in spring (May, June) and autumn (September and October).

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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