What causes fruit tree leaves to turn yellow?
The growth of fruit trees affects the yield and quality of the fruit, and during cultivation, yellowing of the leaves occurs from time to time. What causes this? Are there any remedies?
What causes fruit tree leaves to turn yellow?
1. Disease
Yellow leaves on fruit trees are very likely caused by mosaic virus disease. Mosaic virus disease comes from the rootstock or scion of the fruit tree and may not be obvious in the same year, but as the temperature changes and the tree vigor rises and falls, it gradually becomes apparent.
2. Temperature too high or too low
If the temperature is too high or too low, the leaves of fruit trees will turn yellow. When the temperature stays too high, the leaf stomata enlarge and the leaves turn yellow from water loss. When the temperature stays too low, the leaf stomata close and the leaves turn yellow because their work stops.
3. Herbicide/pesticide damage
When spraying fruit trees with chemicals, if the concentration of the solution is too high, it can easily burn the leaves and cause them to turn yellow.
What should be done when fruit tree leaves turn yellow?
1. Feed the trees early in autumn, apply a corresponding amount of organic fertilizer and medium and trace elements to increase the tree's nutrient reserves; from leaf unfolding to bagging, spray brassinolide two more times, which can also reduce the chance of mosaic disease occurring. This mainly increases the tree's resistance and its antiviral capacity, and the symptoms will naturally ease.
2. When the temperature is too high or too low, take preventive measures. If it is too high, irrigate promptly to replenish water; if the temperature is too low, pay attention to controlling water and take measures to protect against the cold and keep warm.
3. When spraying fruit trees with chemicals, choose low-toxicity, green products and use them strictly according to the instructions.
In addition, a deficiency of elements such as phosphorus, potassium and magnesium can also cause leaves to turn yellow, in which case fertilizer should be applied according to the situation.