How to Treat Borers in Trees: A Brief Guide

Are you wondering how to treat borers in trees? In this post, Petrarca Landcare, Inc., your trusted tree service experts in Akron, Ohio, explains how to stop tree-boring insects in their tracks.

how to treat borers in trees

Cypermethrin Treatment

You must deal with borer insects quickly and effectively. Cypermethrin is an insecticide that acts on contact to kill larvae. It’s effective on insect species that lay their eggs on the bark. 

It doesn’t kill the eggs, but it is lethal to the larvae. You must time the application just right before the larvae can start to tunnel into tree trunks.  

You must also get the dose right, so it’s crucial to measure the infested area. You will need between 0.33 and 0.65 fluid ounces for every 1,000 square feet. It’s essential to dilute the chemical according to the manufacturer’s instructions. 

From there, everything’s easy. Simply put the mixture in a sprayer and shake it well before applying it evenly. 

Spray the solution on the trunks, twigs, and branches to saturate the bark. If you see signs of tunneling, spray the solution there as well.

Use a Systemic Insecticide

When learning how to treat borers in trees, you’ll find it’s best to use a double-pronged approach. Spraying is effective for any tree species, but it’s easy for some bugs to slip through the cracks. 

A systemic insecticide is a soil treatment that kills off any escapees. You apply it to the ground around the tree, and the tree draws it in through the roots. It won’t stop borers tunneling in, but it will kill them if they do. 

Find the correct dose by measuring the tree trunk’s diameter and mixing the solution according to the manufacturer’s directions. Spray it uniformly to drench the ground immediately around the tree’s base. 

What to Do After Treatment

Now you know how to treat borers in trees, it’s time to learn the next steps. It’s critical to take on these tasks to prevent re-infestation and further tree boring.

Evaluate the Damage

If there is too much damage, it’s better to replace the tree. You should remove the tree and the roots and dispose of them correctly. It’s unwise to keep the lumber in your yard, as it might infect other trees. 

You can protect your sapling by applying the above-mentioned treatments proactively. 


If you are keeping the tree, you must provide it with the resources to heal. Give it enough water and feed it if necessary. We recommend performing a soil test to properly correct any deficiencies.  

Then apply a layer of mulch about two to three inches thick, starting about a foot away from the trunk and extending to the outside of the drip line. 


Your next step is to prune the dead or damaged branches. Cut out the infected areas and any branches that might make contact with them. You can then apply treatments again to prevent further issues. 

When pruning, use sharp implements and don’t cut back more than a third of the branches overall. Where possible, try to make symmetrical cuts to balance the canopy out. 

Sealing the Wounds

We normally don’t recommend sealing pruning cuts, but doing so, in this case, is wise as the sap may attract more insects. If you’re unsure of how to proceed, give us a call. 

Contact Us for Professional Advice

Now that you know how to treat borers in trees, why not look into dealing with a tree with damaged bark? Alternatively, hire our team at Petrarca Landcare, Inc. to do all the heavy lifting. Our expert team always gives you the right solution, so call us at (330) 933-0562 to schedule service in Akron, OH, and the surrounding areas. 

Call Now Button