What s wrong with long bean leaves graying? Green beans grow white new leaves, what s going on?

The whitish leaves of beans are usually due to powdery mildew, which is a common disease that usually damages old leaves. Yellow spots appear at the beginning of the disease, which gradually expand and form a layer of powdery powder on the surface of the leaves. At this time, it is necessary to spray with powdery rust**, or other drugs, usually every 10-20 days, and it will get better after two to three times.

What happens to the whitish leaves of peas, what to do if the leaves turn white.

1. Causes of whitishness.

The whitish leaves of peas are usually caused by powdery mildew, and other diseases and pests can also cause the plant to become diseased, but not white. This is a relatively common disease, which occurs in many places in China, mostly in the middle and lower parts of the branches, mainly harming the old leaves, and the damage to the new leaves is usually not serious.

Pea. Second, the manifestation of the disease.

Peas suffer from vitiligo.

Later, in addition to the leaves, there will also be manifestations on the stems and pods. In the initial stage, there will mainly be some powdery yellow spots, after which it will slowly expand to form irregular pink spots with a layer of white powder on the surface, which will affect the photosynthesis of the leaves.

In the long run, the plant will wither and the plant will die. Powdery mildew is transmitted by spores and forms a closed capsule shell in the winter, allowing it to safely overwinter and continue to damage plants until the following spring, and is more common in warm, humid times. You can choose varieties with strong disease resistance to reduce the possibility of its disease, and pay attention to drainage and ventilation.

Green beans with white new leaves are nutrient-deficient, pay attention to reasonable fertilization.

The straight roots of green beans are well developed, and there are symbiotic nodules of different shapes, with a ratio of nitrogen, phosphorus and potassium of 1:1:1, and trace elements such as molybdenum, boron, zinc, and copper are required. Fertilization of legumes and vegetables is aimed at increasing yields.

The specific fertilization methods are as follows:

Apply basal fertilizer. Green bean base fertilizer should be used with delayed decomposition compost, and too much nitrogen fertilizer should not be used as seed fertilizer to avoid rotten seeds. Usually 1000-1500 kg of high-quality organic fertilizer is used per mu, and 1-2 kg of microbial fertilizer is added. Usually applied to a depth of 8-10 cm.

Topdressing. Green beans need medium fertilizer, according to the principle of "base fertilizer as the mainstay, top dressing as the supplement". Nitrogen fertilizer should be applied thinly to seedlings, and the concentration should be increased appropriately with the growth of plants. Usually 10-15 kg of compound fertilizer is applied per mu, and kg of microbial fertilizer is applied with water.

Top dressing outside the roots. Foliar spraying was carried out at the full flowering and final flowering stages with urea, ammonium sulfate, superphosphate leaching solution and other conjugated powder-based microbial agents. Usually 1-2 kg of urea, 1-2 kg of potassium dihydrogen phosphate, and 40-50 kg of water are added per mu.