Yellow bean leaf yellow is often encountered by many vegetable farmers who grow beans, but there are many reasons for the yellowing of leaves, and some causes may even result in a complete loss of production if they are not treated promptly. Some of the causes of yellowing of the bean pods will now be described below.
First, the symptoms
Yellow leaves of beans are two main conditions. One is that the bottom leaves are yellow, easy to fall off, and gradually expand upwards, causing dead trees. The second is the yellowing of the top new leaves, often accompanied by falling fruit. The third type is that the plants will not die, but the leaf veins of plants will be yellowed in the middle.
Second, the cause analysis
1. Root bean rot disease, commonly known as "red root disease." This is a kind of soil-borne disease. The pathogens in the early stage infested the root system, the plants were malnourished, and the bottom leaves were yellow. The plants wilted at noon and recovered sooner or later, eventually resulting in dead trees.
2. Lack of trace elements. The leaves at the top growing point appeared yellow-white and caused by iron deficiency and zinc. The yellow leaves on the top of the new leaves usually occur after the shade suddenly emerges, the roots grow poorly, the weather changes from cold to warm, and the early plant results are too many.
3. Plant growth is poor. This situation will not cause the plant to die, mainly because of poor plant growth, resulting in yellowing of the middle and lower leaves and veins, which can easily lead to premature plant failure. For example, high temperatures in greenhouses, poor root development, injures of roots, and unscientific supply of fertilizer and water can all cause similar situations.
Third, control methods
1. Root rot of beans can be treated with pesticides. The agent can be selected: carbendazim thiram (Icylicin) + hymexazol + copper rosinate root.
2. In the bad weather and late stage of plant growth, foliar spray can be used: Amino Acid foliar fertilizer (chelating various trace elements such as boron, calcium, magnesium, iron and zinc), which can effectively alleviate the yellow and white of the top new leaves.
3. To increase plant resistance, cultivate strong root systems, and use water for fertilizers to prevent yellowing of the veins and premature aging of the leaves.
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