Fruit Tree Leaves Turning Yellow

A fruit tree’s leaves normally change color around autumn as they enter a period of senescence, or winter dormancy. However, if the fruit tree’s leaves start turning yellow when it is not yet autumn, it can be alarming. This article will help you understand the reasons fruit tree leaves tend to turn yellow, and how to address the issues.

Fruit Tree Leaves Turning Yellow: What Are The Reasons?

Changes in the weather 

As mentioned earlier, fruit tree leaves tend to turn yellow during the cold months to prepare for the winter dormancy period. The fruit trees withhold nutrients and water from certain parts and, as a result, photosynthesis does not take place and the chlorophyll levels drop. 

The leaves turn yellow in the absence of chlorophyll, which is what gives plants their green color. Without the vital nutrients, they eventually fall off.

There is no need for any treatment, as this is part of the tree’s natural life cycle. 

Lack of, or too much, water 

Fruit trees may become stressed if they are given too much or too little water. If they do not receive adequate water for their needs, it could result in drought stress. Similarly, overwatered fruit trees tend to appear droopy and may develop root rot. The roots also become incapable of absorbing nutrients.

Watering inconsistencies could lead to yellowing leaves that eventually fall off. It may also increase fruit drop. Fruit tree varieties with shallow roots are less tolerant to drought. 

To fix the issue, water the fruit trees as soon as you notice signs of underwatering. If the trees are overwatered, hold off watering for a while. Plant trees in a well-drained location and allow the top few inches of soil to dry out before the next watering. 

Nutrient deficiencies

Fruit tree leaves could also turn yellow due to nutrient deficiencies. Nutrients that are essential for trees and plants include zinc, manganese, copper, sulphur and magnesium. If these nutrients are lacking in the soil, it could lead to reduced photosynthesis which results in yellowing leaves. In this case, the tree will not be able to produce sufficient energy for fruit development. 

A common sign of iron deficiency includes yellowing near the leaf veins. As this progresses the whole leaf turns yellow, with bright green veins. The yellowing begins on the new growth and makes its way throughout the tree. 

Manganese deficiency manifests the same symptoms. In this case the older foliage is affected, while in severe cases the younger leaves will be affected.

To fix the issue, perform a soil test so that you know what nutrients are lacking and what measures to take. You should apply fertilizers to boost the presence of nutrients in the soil. 

Chelated iron addresses iron deficiency, while sulfur may be applied outside the tree drip line. Sulfur raises the acidity of the soil and allows nutrients to become more easily accessible to the fruit trees.

Diseases or pests 

Certain diseases associated with yellowing and falling leaves include the following:

  • Necrotic leaf rot

This disease usually invades apple trees and starts with brown blotches on the leaves, which eventually turn yellow and drop off. To treat this problem, apply fungicides with zinc ions to the affected fruit trees. 

  • Apple scab

This fungal disease appears on the leaves and fruits and is characterized by pale yellow spots on the upper side of leaves along with darker spots on the lower side. Copper fungicide is effective in treating this disease. Apply the fungicide at least every seven to 10 days until the fruit trees are revived. 

Pest infestation could also result in yellowing leaves. Aphids could invade the fruit trees and suck the sap or juice from the leaves, making the trees vulnerable and weak. To fix this, apply insecticidal spray or neem oil to control and eradicate the pests. 

Conclusion 

Fruit trees normally undergo leaf color changes during the cold months to prepare for the winter dormancy period. However, fruit tree leaves yellowing when it is not yet autumn may signify an underlying problem. The common reasons for this include overwatering, underwatering and nutrient deficiencies. It may also be due to diseases like apple scab and necrotic leaf rot, or a pest infestation.

Image: istockphoto.com / TommyIX