What is the reason for the yellow spots on grape leaves? How to treat yellow leaves

1. Reasons for yellow spots on leaves

1. Unsuitable soil: The yellow spots on its leaves are mostly due to infection with yellow leaf disease, which is usually caused by iron deficiency in the soil. The soil contains too much calcium carbonate, which causes the soluble iron salt to become insoluble. The roots cannot absorb it normally, and the physiological state becomes unbalanced over a long period of time, which makes this disease prone to occur.

2. Improper fertilization: It may also be caused by improper fertilization. The applied fertilizer is not well-composted, such as chicken manure, sheep manure, etc., which are also prone to yellow leaf disease. Be especially careful when fertilizing and do not use raw fertilizer.

3. Lack of water: Water is indispensable during the growth period. If the soil is dry for a long time, the roots cannot absorb water and cannot provide water to the branches and leaves normally, yellowing leaves are likely to occur. Especially new seedlings or plants with floating roots.

II. Prevention and Control Measures

This disease must be prevented and controlled in advance. Before setting the value, ditches should be dug and water should be irrigated to wash the alkali and remove the salt from the soil. Apply decomposed organic fertilizer once every year after the fruits have grown. It is recommended to do this in autumn before burying the soil and entering winter. During the growth period, compound fertilizer should be applied regularly to ensure that it has sufficient nutrients and does not suffer from nutrient deficiency. In addition, if yellow leaf disease is found, medicine should be sprayed as soon as possible. The medicine can be a mixture of ferrous sulfate and citric acid. Spray every 7-10 days. It is best to spray on a cloudy day and avoid the scorching sun.