Harmful downy mildew don't be afraid to return the rose to health immediately

Hearing the word downy mildew, many flower friends who have rose at home may change their color. Downy mildew is a kind of disease which is harmful to rose, and the disease is developing rapidly. if the relevant effective measures are not found and taken in time, the consequences will be unimaginable, and the disfigurement of rose is an inevitable result. the serious whole plant will die.

The condition of downy mildew can be judged by the color of the leaves. At the beginning of the disease, there are usually some light green markings, that is to say, you will find that the color of the leaves of the rose has begun to change color. This is a sign that something is wrong!

As the disease develops, the range of these markings gradually expands, and the color gradually darkens, turning yellowish brown, then purplish brown, and finally dark brown. As the color deepens step by step, it shows that the condition is becoming more and more serious. The site of the disease is not limited to leaves, just growing buds, buds, pedicels are extremely easy to catch the disease.

Leaves infected with downy mildew will turn yellow and fall off, and new buds and buds will shrink and rot and die. In a cloudy and rainy day, a layer of frost mildew as white as frost can be observed on the back of the infected leaves.

The serious period of downy mildew is often in spring and autumn, especially in the rainy spring, Rain Water is more, the air is moist, and it is easy to get sick if put indoors. High air humidity and poor ventilation are the main causes of the disease, of course, if the branches and leaves are too dense, it is easy to be poorly ventilated, and another point is that too much nitrogen fertilizer will easily get sick (what did nitrogen fertilizer do wrong?! ).

It is suggested that a big pruning can be carried out in winter, because downy mildew germs are easy to start latent in winter, proper pruning can reduce the latent beds of germs, and on the other hand, they can also save energy for the coming spring. When you put the rose indoors for shelter from the rain in spring, you should pay attention to the ventilation by opening the window. If the weather is fine, you can move to the outdoor ventilation place.

Fertilization should be balanced, the proportion of nitrogen, phosphorus and potassium fertilizer should be balanced, while phosphorus and potassium fertilizer can greatly improve the plant disease resistance, too much nitrogen fertilizer is easy to get sick. Do not spray directly on the branches and leaves when fertilizing. The commonly used treatment after being infected with downy mildew can be sprayed with 70% chlorothalonil 800 times or 80% Dysen zinc 800 times, once a week, 3-5 times continuously.