Causes of Yellowing Grape Leaves and How to Fix Them

Grapes are a vine plant, and problems are unavoidable during cultivation, such as yellowing leaves, which is a common phenomenon. So what causes grape leaves to turn yellow? How should you fix it? Let's take a look at the detailed introduction below.

1. Improper watering

Water shortage or overwatering of grapevines can both cause leaves to turn yellow or wither. When the plant lacks water, chlorophyll in the leaves naturally decreases due to the water shortage, and the leaves turn yellow. When overwatered, the roots take up too much water, which weakens oxygen transport and also causes the leaves to turn yellow.

Solution: Grape watering must be done in moderation, and the amount of water should be determined by the weather. In summer, when it is dry and hot, you need to water frequently to replenish moisture. During the rainy season, watering should not be done, and you should also pay attention to drainage measures to prevent excessive water accumulation in the soil.

2. Improper fertilizing

During cultivation, improper fertilizing can also cause grape leaves to turn yellow. Fertilizing too frequently leads to excess nutrients in the soil, and fertilizer burn in the plant causes the leaves to turn yellow. But if fertilizer is applied poorly and the nitrogen, phosphorus and potassium nutrients in the soil are not guaranteed, the plant will also gradually turn yellow and wither due to nutrient deficiency.

Solution: The amount of ordinary fertilizer applied must be well controlled, and you should apply light fertilizer frequently. Fertilizing too often is not advisable, especially when applying phosphorus and potassium fertilizers; be sure to loosen the soil appropriately, so that the leaves can stay emerald green and lush.

3. Phytotoxicity

Grapevines suffer from pest infestations during growth, so many fruit growers spray pesticides for prevention. However, sometimes improper spraying can also cause the plant's leaves to turn yellow; this is phytotoxicity. Yellow leaves caused by phytotoxicity cover a large area, and in severe cases can lead to plant death, making it extremely harmful.

Solution: When spraying, pay attention to the method and the concentration of the pesticide. When phytotoxicity occurs, water the plant and spray it with water to reduce the pesticide concentration, and appropriately increase the light duration to strengthen photosynthesis, alleviating the phytotoxicity so the plant can recover.

4. Diseases

When a grape plant suffers from leaf spot disease, yellowing leaves also appear. Leaf spot disease is caused by infection with certain fungi and pathogens. This disease causes localized leaf necrosis, which then gradually spreads. In addition, scale insects and red spider mites can also cause grape leaves to turn yellow.

Solution: When leaf spot disease occurs on grapes, promptly spray the whole plant with a 500-fold dilution of 50% carbendazim. For scale insects and red spider mites, you can scrub them with a toothbrush dipped in soapy water, then spray with insecticide for control.

The above is an introduction to what to do when grape leaves turn yellow. We hope it helps you. For more related knowledge, please stay tuned to us.