Common Tree Pests: What You Need to Know

If you’re a homeowner, then you know that maintaining your property can be a lot of work. One of the most important aspects of home maintenance is taking care of your trees. Unfortunately, trees can often be targeted by pests and diseases.

In this guide, we will discuss some common tree pests, and what you need to know about them. We’ll also provide tips on how to protect your trees from these pests.

14 Common Tree Pests

Tree pests can come in many different shapes and sizes. Some common tree pests include:

1. Aphids

Aphids are small, sap-sucking insects that can infest trees and shrubs. Aphids typically congregate on the new growth of plants and fruit trees, where they can cause stunted growth and premature leaf drop.

Aphids can also spread diseases from plant to plant. If you notice aphids on your trees, you should contact a professional pest control company to get rid of them.

2. Beetles

There are many different types of beetles that can infest trees, including the Asian longhorned beetle, the emerald ash borer, and the gypsy moth. Beetles typically eat the leaves of trees, which can cause extensive damage.

Beetles can also bore into the wood of trees, causing even more damage. Trees infested with beetles are often unhealthy, and can eventually die.

3. Caterpillars

Caterpillars are one of the most common tree pests, and can be very damaging to your trees. They eat the leaves of your trees, which can cause the tree to become stressed and weak.

Caterpillars can also carry diseases, which can spread to your other plants and trees. If you see caterpillars on your trees, you should remove them as soon as possible.

4. Scale Insects

Scale insects are small, sap-sucking pests that can infest trees and shrubs. They attach themselves to the plant and feed on the sap, which can weaken and even kill the plant.

There are several different types of scale insects, including armored scales, soft scales, and mealybugs. This pest is most common in warm, humid climates.

5. White pine weevil

The white pine weevil is a serious pest of evergreen trees, shrubs, and ornamentals in the northern United States. The adult weevil feeds on the buds and new growth of these plants, causing distortion and stunting.

This damage can kill young trees, and make older ones more susceptible to disease and insect infestation. Look for small, brownish-black weevils with long snouts feeding on new growth at the tips of branches.

Control this pest by pruning off infected branch tips, and disposing of them in the trash. You can also use an insecticide labeled for white pine weevil control.

6. Shade tree borers

Shade tree borers are a group of insects that attack and kill many different types of trees. The most common type of borer is the Emerald Ash Borer (EAB). EAB is a destructive pest of ash trees.

It was first discovered in North America in 2002, and has since spread to 24 states and two Canadian provinces. EAB attacks all species of true ash trees (Fraxinus spp.), including green, white, black, and blue ash. It is responsible for the death of tens of millions of ash trees across North America.

7. Pales weevil

The pales weevil is a common pest of fruit and nut trees. The adult weevils are small, dark-colored beetles that feed on the leaves of these trees. The larvae of the pales weevil are white, legless grubs that live in the soil, and feed on the roots of these trees.

Pales weevils are most active in the spring and summer months. They can cause significant damage to trees if left unchecked.

8. Ips beetles

Ips beetles are small, dark-colored beetles that attack a variety of trees, including pines, spruces, and fir trees. Ips beetles bore into the bark of trees, and lay their eggs inside the tree.

The larvae feed on the inner bark of the tree, causing extensive damage. Ips beetles can kill trees within a few years if left unchecked.

9. Asian longhorn beetle

This invasive species was first found in the U.S. in 1996, and has since spread to more than a dozen states. The Asian longhorn beetle is a serious threat to hardwood trees, and has no known predators in North America.

This pest bores into tree trunks and branches, causing extensive damage that can ultimately kill the tree. If you think you’ve spotted an Asian longhorn beetle, it’s important to contact your local forestry department immediately.

10. Balsam wooly adelgid

These pests are small, aphid-like creatures that feed on the sap of Fraser fir trees. They suck out so much moisture that the tree’s needles turn brown and drop off, and eventually, the tree dies.

Balsam wooly adelgids can kill a Fraser fir in just two years. Look for these pests on the undersides of needles, where they’ll appear as small, white, cottony masses.

11. Black turpentine beetle

The black turpentine beetle is a common tree pest that attacks several species of coniferous trees, including pine, fir, and spruce.

The adult beetles are black, and about 0.25 inches long. They bore into the bark of trees to lay their eggs and feed on the sapwood. This feeding can damage and even kill trees.

12. Carpenter ants

Carpenter ants are a common type of ant found in the United States. These ants are black or brown, and range in size from one-quarter to one-half inch long.

Carpenter ants are attracted to wood that is moist or has been damaged by other insects. These ants tunnel through wood, causing damage to trees and buildings.

13. Douglas-fir bark beetle

The Douglas-fir bark beetle (Dendroctonus Pseudotsuga) is a species of bark beetle native to North America. It is a major pest of Douglas-fir trees, and has also been known to attack other species of coniferous trees.

The Douglas-fir bark beetle is attracted to stressed or damaged trees, and can quickly infest an entire tree, causing it to die. The beetle produces a pheromone that attracts other beetles to the area too, which can lead to large-scale infestations.

14. Douglas-fir tussock moth

Douglas-fir tussock moth caterpillars are common pests of Douglas-fir trees. The caterpillars are about one inch long and have black, white, and brown stripes running the length of their bodies.

They feed on the needles of Douglas-fir trees, which can cause the needles to turn brown and drop off the tree. If a tree is heavily infested, it may lose all of its needles and die.

Tips On How to Protect Your Trees From Pests

By protecting your trees from pests, you can help ensure the health of your trees, and the beauty of your landscape. Here are a few tips on how to protect your trees from common pests:

  • Inspect your trees regularly - Look for signs of pests, such as holes in the bark or leaves and branches that are dying or dead.
  • Remove sick or damaged trees - If you find a tree that is infested with pests or is otherwise sick or damaged, it should be removed from your landscape.
  • Maintain healthy trees - Healthy trees are less likely to be attacked by pests. Be sure to water your trees regularly, and fertilize them according to their needs.
  • Prune dead or dying branches - Dead or dying branches are more likely to be infested with pests. Pruning these branches can help prevent an infestation from spreading.
  • Hire a professional - If you are concerned about the health of your trees, or if you suspect that they are infested with pests, it is best to hire a professional tree service. A professional can help assess the health of your trees, and treat them for any pests.

By following these tips, you can help protect your trees from common pests. By doing so, you can also ensure the health and beauty of your landscape.

Frequently Asked Questions

No, mountain pine beetles and western pine beetles do not kill all pine trees. These beetles prefer to infest stressed or damaged trees. Healthy trees are less likely to be attacked by these beetles.

Planting trees does not help prevent mountain pine beetle infestations. These beetles are native to North America, and will infest trees regardless of whether they were planted or not.

No, Japanese beetles and branch dieback do not kill all trees. These pests prefer to infest stressed or damaged trees. Healthy trees are less likely to be attacked by these pests.

No, forest tent caterpillars are not harmful to humans. These caterpillars only feed on leaves, and do not pose a threat to people. However, if you are allergic to caterpillars, you may experience an allergic reaction if you come into contact with them.

Trees are an important part of any landscape, but they can be susceptible to pests. There are a number of common tree pests that can cause damage to trees, including carpenter ants, Douglas-fir bark beetles, and emerald ash borers. 

By inspecting your trees regularly and taking steps to protect them from pests, you can help ensure the health and beauty of your landscape. If you find yourself having to deal with an infestation of these pests and you aren’t sure what to do, don’t hesitate to call a professional for advice or assistance.