Orange Tree Leaf Spots

Orange size reduction may result from leaf spot diseases.

Leaf spot diseases on orange trees are caused by fungus infections. While most leaf diseases will not kill a tree entirely, they should still be eliminated to avoid excessive leaf drop and promote healthy fruit.

Symptoms

Leaf spots on orange trees typically begin as small round spots, sometimes raised, that range in color from brown and black to yellow. Spots will increase in size if left untreated, often thriving in damp conditions.

Effects

Leaf spot diseases cause leaves to turn yellow and wither. Leaves will drop from the tree prematurely, decreasing the overall health of the tree. Leaf spot diseases can also hinder the growth of fruit.

Control

Keeping a tree in overall health is the best way to prevent leaf spot from thriving. Prune trees annually, taking special care to remove all diseased branches or dead wood. Leaf spot diseases that respond to fungicide should be treated with chemicals at the first sign -- apply at least two treatments at seven-day intervals.

References

• University of Illinois Extension: Fungal Leaf Spot Diseases of Shade and Ornamental Trees in the Midwest