What Are Oak Galls And Are They Treatable?

If you notice strange galls on your oak tree's leaves and branches, you may have an oak gall wasp infection. While a few galls won't likely harm your healthy tree, a severe infestation can potentially cause harm. In addition, traditional insect treatments may be ineffective with gall wasps. However, you and your tree service can do something to reduce the impact of these oak gall wasps. Here is more information about oak galls and managing an infested tree.

What Are Oak Galls?

Oak galls are bulges or swellings in tree branches, twigs, or leaves. Various species of oak gall wasps create them to support their larvae until they can pupate and emerge as adult wasps. Galls on the branch or twigs usually come in two different types: gouty and horned galls. Which kind your trees get depends on the wasp species and where the larvae are in their life cycle.

Why Do Oak Galls Form?

Oak galls form as a reaction to the wasp's breeding cycle. Oak gall wasps have a complicated breeding cycle that sometimes spans more than one year. These wasps may utilize different parts of the tree depending on their maturity and species.

The chemical reactions to the wasp's egg and larvae cause changes to the tree's tissue and vascular system. The gall houses and feeds the larvae until they are ready to emerge as adults. Horned oak galls often form when certain species' larvae reach a specific size or maturity.

How Do Oak Galls Affect Trees?

Most of the time, oak galls affect the tree very little. If your tree is healthy and only has a few galls, it should handle the infestation well. The wasps are harmless to humans, and many species are very tiny, so you may not even see them. Sometimes the galls damage the plant's vascular system and interrupt photosynthesis. The tree may not be able to transport vital nutrients and could weaken.

Are Oak Galls Treatable and Preventable?

You may be able to control oak galls by pruning the infected branches and destroying the galls. However, you are unlikely to completely prevent an infestation. One of the best things you can do is ensure that your tree is as healthy as possible with proper watering and fertilizing. Older trees, especially, need extra vigilance.

Oak galls are unsightly, but you can manage them as long as your tree is healthy. Your tree service can help spot and manage gouty and horned oak galls and take appropriate steps to control them. Ask your service about any possible new treatments as well. Don't attempt to chemically treat your trees yourself. Call a tree service first for advice and an evaluation.

For more information on gouty oak galls, contact a professional near you.