How to treat cucumber powdery mildew

1. Symptoms of the disease

Powdery mildew, also known as white hair disease, mainly harms the leaves of cucumber, followed by the petioles and stems, but does not harm the fruit. In the early stages of the disease, there will be white circular powdery spots on the front and back of the leaves, which will then turn into larger white powdery areas and eventually cover the entire leaf. After wiping off the white powder, you will find that the leaves become withered, yellow and brittle. In more severe cases, the leaves will turn gray and the entire leaf will die. This disease affects the photosynthesis of the leaves, interferes with metabolism, and thus inhibits the growth of the plant.

2. Causes

There are many possibilities that may cause powdery mildew on cucumbers. For example, if the planting density is too high and the plants have poor ventilation and light transmission, it is easy for fungi to grow. It may also be due to the heavy stickiness of the soil and insufficient fertility, which leads to reduced disease resistance of the plant. In addition, if the fertilizer is not fully decomposed, it can also cause disease. It is also prone to disease if it grows in a warm and dry climate with insufficient light, or in a long period of dryness after continuous rain.

3. Treatment Methods

In the early stages of the disease, you can use Kaiser dry suspension, Cuibei dry suspension, Shigao water-dispersible granules, Luying emulsifiable concentrate and other agents to make a solution for spraying. Mainly spray on the affected area, generally once every 7 days, and it can be cured by spraying 2-3 times in a row. In addition to these agents, fumigation treatment can also be carried out with chlorothalonil or chlorpyrifos smoke, usually in the evening.

4. How to prevent

If you want to prevent it, you must first choose the right variety. Some disease-resistant varieties have strong resistance to this disease. In addition, it is necessary to control the planting density, do a good job of drainage, regularly check and remove old and diseased leaves, pay attention to increasing light transmission and ventilation, and appropriately supplement phosphorus and potassium fertilizers to provide disease resistance.