What about rose powdery mildew?

Powdery mildew is a common disease of rose, which can harm many plants of Rosa. Sick rose will cause sick leaves curl, scorch, tender shoots can die, flowers can not open or irregular flower posture, affecting the growth and ornamental value of the plant.

Powdery mildew generally harms the leaves, tender shoots, buds and pedicels of rose. After the young leaves were infected, the leaves shrunk, curled and sometimes turned purplish red, while after the old leaves were infected, there was a nearly round, watery chlorotic macula, which was not much different from the uninfected leaves. In addition, there will be something white on the diseased spot on the back of the leaves of the sick plant.

Prevention and cure method

1. Control fertilizer and water

Strengthen cultivation management and water reasonably according to the wetting condition of the soil. In the aspect of fertilization, nitrogen fertilizer should not be applied too much, and potassium and calcium fertilizer should be applied appropriately to enhance plant growth, maintain strong plants and improve plant disease resistance. in addition, reasonable control of the distance between plants can also effectively inhibit the occurrence of 100% disease.

2. Timely pruning

If diseased plants are found, they should be pruned in time to remove diseased shoots and diseased leaves. In addition, the ventilation and light transmission conditions between plants should be improved. Indoor potted rose should be placed in a well-ventilated and well-lit environment. In winter, it is necessary to control indoor temperature and humidity, and pay attention to ventilation at night.

3. Drug prevention and treatment

Before the onset of the disease, can be sprayed 200 Mel 300 Bordeaux solution or lime sulfur table agent, once every two weeks, even spraying 3 Mel 5 times can be prevented.

Rinse the disease department with detergent solution for 3 minutes and rinse with clean water once every other day. After 3 times, the harm can be reduced.

If the disease has occurred, you can spray sulfur preparation, wrap the sulfur powder in a coarse cloth. Knead it in water to make a suspension spray, which is usually sprayed once every 7 days; when the disease is serious, it can be sprayed every 3 days for 3 times, and a better prevention and treatment effect can be obtained. Boric acid solution can also be used to spray, boric acid solution can not only control the spread of powdery mildew, but also promote the flower buds to bloom as usual, but also does not affect the growth of diseased branches and leaves, and the effect is good. Prepare with 1 gram of boric acid and 1000 grams of water. Spray the affected area after coordination. Spray should be comprehensive, especially the back of the leaf should be sprayed, and then spray every 3 days. It can also be sprayed with 1000 times of thiophanate methyl or 80-1000 times of Dysen zinc. But do not spray when the temperature is higher than 32 ℃, so as not to burn leaves.

Powdery mildew has a more obvious feature, that is, there will be powdery white objects at the affected site, so flower friends should take corresponding measures in time when discovering powdery mildew to avoid the spread of the disease.