Controlling Cherry Tree Borers: How to Protect Your Trees

If you're a cherry tree lover, you know how frustrating it is to see your beloved trees become infested with borers. These insects can cause serious damage to your trees and significantly reduce their fruit yield. However, there are ways to control cherry tree borers and keep your trees healthy.

What are Cherry Tree Borers?

Cherry tree borers are the larvae of several species of clearwing moths. These moths lay their eggs on the bark of cherry trees, and when the eggs hatch, the larvae burrow into the tree's trunk or branches. Once inside, they feed on the tree's cambium layer, causing wounds that can weaken the tree and make it more susceptible to disease and other pests. If left untreated, cherry tree borers can kill a tree in just a few years.

Identifying Cherry Tree Borers

The first step in controlling cherry tree borers is to identify them. Look for signs of borer infestation, such as sawdust-like frass around the base of the tree, oozing sap, and wilting or yellowing leaves. You may also notice holes or splits in the bark where the borers have entered the tree. If you suspect that your tree has borers, you can confirm your diagnosis by cutting into the affected area and looking for the larvae.

Prevention Techniques

The best way to control cherry tree borers is to prevent them from infesting your trees in the first place. Here are some prevention techniques:

1. Plant resistant varieties: Choose cherry tree varieties that are less susceptible to borers, such as Montmorency and Balaton cherries.
2. Clean up debris: Remove any fallen leaves, branches, or other debris around your trees, as these can provide shelter for the borers.
3. Prune your trees: Regular pruning can help keep your trees healthy and less attractive to borers.
4. Apply insecticide: Apply an insecticide containing carbaryl or permethrin to the trunk and branches of your trees in the spring and fall to prevent borers from laying eggs.

Treatment Techniques

If your cherry tree is already infested with borers, there are still some treatment techniques that you can try:

1. Physical removal: Use a knife or wire to carefully remove the borer larvae from your tree. This technique is only effective if there are a small number of larvae present and they haven't yet caused significant damage.
2. Inject insecticide: In severe cases, you may need to inject an insecticide directly into the tree's trunk to kill the larvae. This should only be done by a professional arborist.
3. Use beneficial nematodes: These tiny worms can be applied to the soil around your tree to kill the borer larvae. However, this technique is only effective if the larvae are close to the soil surface.

Cherry tree borers can be a frustrating problem for gardeners, but with the right techniques, you can control them and keep your trees healthy. By planting resistant varieties, cleaning up debris, pruning your trees, and applying insecticides, you can prevent borers from infesting your trees. If your tree is already infested, physical removal, insecticide injection, or beneficial nematodes may be effective treatments.

An example of a cherry tree borer (Photo by David Cappaert, Michigan State University)

Cherry trees, gardening, pest control, tree health, fruit trees