Horned Oak Gall Wasp in Southern Maryland


Your oak trees may be at risk of a horned oak gall wasp infestation, which can affect their health. Find out more about this pest and what to do.

Around 2 million Americans are allergic to the venom of stinging bugs. This includes bees, hornets, and wasps.

But when it comes to wasps, their sting isn’t all you have to worry about. Some types of wasps can cause harm to your beautiful trees, such as the horned oak gall wasp.

In this article, we’ll tell you what you need to know about the horned oak gall wasp in Southern Maryland.

What Is the Threat?

The horned oak gall wasp (or Callirhytis cornigera) is a pest that attacks oak trees. They create galls on young branches, which look like horned brown balls about the size of a golf ball.

What’s sneaky about this pest is that the galls take 3 years to develop completely. Then, the female wasps come out of the gall in the springtime and lay eggs on the tree’s leaf buds.

The wasp larvae make new, smaller galls and then exit these in early summer. After mating, they’ll put their eggs into the young oak twigs. These will grow over the next 2 years, grow “horns”, and the wasps will keep proliferating.

This abnormal tissue growth over the years will prevent the tree from getting proper nutrients and water. This then causes the tree to become disfigured and it can even experience dieback.

Where Is the Threat?

You’ll find thisl wasp all throughout the Midwest, as well as south of Georgia. They’re also found in Southern Canada. In recent years, there have been heavy infestations on pin oak trees in the states of Indiana, Kentucky, and Missouri.

The horned oak gall wasp likes to attack other oak species such as black, blackjack, willow, and water.

Symptoms of the Horned Oak Gall Wasp

As mentioned above, the wasps make galls in oak trees. As a result, the leaves will yellow, the canopy will thin, and limbs will fall off. In the worst-case scenario, you’ll have a dead tree.

These galls affect young and old trees severely, although in many cases, young trees are more affected.

What to Do About the Problem

To take care of existing wasps, you can try to prune and/or destroy infested twigs and branches. To kill the larvae, burn or step on them. If you can pull off the galls, seal them in a bag and discard.

You’ll need to have a tree specialist apply an injection treatment to prevent new galls. These experts can also prune your trees and apply a nutrient booster to help them bounce back to a healthy and full look.

Get Rid of Your Wasp Issue

As you can see, the horned oak gall wasp can cause a lot of damage to oak trees if left to its own devices. To prevent tree disease and death, make sure you call a tree specialist as soon as you notice galls on your gorgeous oak trees.

For tree services in Southern Maryland (including wasp treatments), book us today.


Contact us for a free quote.

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