Tree Borers Identification: How to Identify Them?

Elvin Carico

By Elvin Carico

Last Updated on November, 2024

Tree borers are insect species that are sneaky little pests, and they can wreak havoc on your beloved trees before you even know they’re there. Identifying them early is crucial if you want to save your trees from severe damage or even death.

Let’s jump right into the key signs that your tree might be under attack by these destructive insects.

Quick Summary

  • Early identification of tree borers is crucial. Key signs include sawdust-like material (frass) around small holes, oozing sap, and swollen or cracked bark.
  • Tree borers are insects, often in their larval stage, that feed on the inner bark or wood. They primarily target weakened trees, but some species, like the emerald ash borer, can attack even healthy trees. Different species target specific types of trees.
  • Managing a borer infestation can be challenging and may require removing severely damaged trees. Prevention is key—keeping trees healthy, monitoring them regularly, and avoiding trunk injuries can help prevent infestations.

How to Identify Tree Borers?

Spotting the First Signs

image of a tree borer beetle

One of the first clues that tree borers are at work is the appearance of sawdust-like material around small holes in your tree’s trunk or branches. This material, also known as frass, is one of the telltale symptoms that borers are chewing through the wood.

You might also notice sap or resin oozing from these tiny holes, sometimes accompanied by swelling or cracking in the bark.

If you see areas of tree bark that look swollen, knotty, or callused, it’s time to take a closer look. These symptoms are your tree’s way of crying out for help.

The Destructive Nature of Tree Borers

Tree borers are insects, usually in their larval stage, that feed on the inner bark or wood of tree trunks, branches, twigs, as well as tree roots.

They’re particularly drawn to trees that are already struggling or are in poor health, such as those newly planted or weakened by drought, disease, or physical injury.

However, non-native borers like the emerald ash borer don’t discriminate—they’ll attack even healthy trees, and weaken branches and the trunk. So, if your ash trees or other vulnerable species like birch, poplar and willow trees are in the vicinity, be on high alert.

Types of Tree Borers

Tree trunk damaged by an insect brorer

There are several species of tree borers and they come in many forms, and knowing the type of borer insects you’re dealing with can help in managing the problem. Common culprits include: 

  • Ash/Lilac borers
  • Bronze birch borer
  • Bark beetles
  • Locust borer
  • Longhorned beetles
  • Flathead borers

Each of these species targets specific types of trees. For example, the emerald ash borer species primarily targets ash trees, while the bronze birch borer goes after birch trees.

Meanwhile, the peachtree borer, flatheaded appletree borer, and rhododendron borer prefer fruit trees and ornamental plants, and the poplar and willow borer, as the name suggests, attack poplar and willow species. Flatheaded borers generally favor any type of tree with broad leaves.

Managing a Borer Infestation

Person holding a timber piece

Once you’ve identified a tree borer problem, acting quickly is crucial. Unfortunately, treating tree borers can be challenging, especially if the adults are already present and laying eggs throughout the tree.

In cases where the tree trunk and infested branches are riddled with holes and winding tunnels, it might be easier—and more effective—to replace the tree than to treat it. Extensive damage can occur after just a few seasons, leaving the tree structurally unsound and beyond saving.

That said, there are some steps you can take to manage borer attacks. Sticky traps near exit holes can catch adult borers before they lay eggs, while chemical treatments like a systemic insecticide can be applied to the soil or directly to the tree to kill tree borer larvae as they feed.

For high-value trees, it may be worth consulting a professional arborist, who can recommend the best course of action based on the type of borer insects, and the extent of the damage.

They will be able to advise whether applying systemic insecticides to the trunk and branches, or removing the infected trees, is best.

Prevention is Key

The best way to deal with tree borers is to prevent infestations in the first place. Keeping your trees in good health is the first line of defense against borer attack. Water them regularly, especially during dry spells, and mulch around the base to protect the roots.

Avoid mechanical injury to the trunk, as wounds can attract most borers. If you’ve planted new trees, monitor them closely for signs of stress or infestation, as young trees are particularly vulnerable.

Regularly inspect your trees for signs of borers, particularly during late spring when adult insects are most active. Look for small holes, sawdust-like frass, and oozing sap. If you spot any of these symptoms, don’t wait—take action immediately to prevent the infestation from spreading.

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When to Call in the Professionals?

treatment for Pine beetle

If you’re dealing with a severe tree borer infestation or if you’re unsure about the health of your trees, it’s time to call in the experts. At Tree Removal San Antonio, we specialize in identifying and treating borer infestations, among other tree-related services.

We can help you assess the situation and determine the best course of action, whether it’s treating the tree or removing it to prevent the spread of borers to nearby trees.

Staying vigilant and acting quickly are your best tools in the fight against tree borers. By knowing what to look for and taking preventive measures, you can manage tree borers and keep your trees healthy and beautiful with new growth, for years to come.

FAQs

Tree borer damage is identified by small holes in the bark, sawdust-like material at the base, dead or dying branches, and peeling or cracked bark. Infected trees may also show signs of wilting or premature leaf drop.

You can tell if you have borers by looking for small, round or oval exit holes in the tree’s bark, sawdust-like frass around the base or on branches, and dead or wilting branches. You might also notice peeling bark or sap oozing from the holes.

Borers are insects that typically have elongated, cylindrical bodies. Depending on the species, they can be beetles or larvae (grubs) that burrow into wood. Adult borers often have hard, shiny shells, while their larvae are usually creamy-white with soft bodies and brown heads. The larvae are the ones that tunnel through the wood, causing the most damage.

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