Vermont Summer Tree Pests to Watch Out For

All trees are vulnerable to insect infestations that can cause illness or even death. While different trees and regions experience various types of insects and related diseases, here in Vermont, we have some pests that have created problems for years and others that are new to our area.

That’s why it’s important to inspect the trees on your property regularly to spot signs of a pest infestation. Catching a problem early allows a skilled arborist to identify the type of pest and put a plan into place to restore the tree or shrub to a healthy condition.

Here are some of the main pests that impact our trees in Vermont and what to be on the lookout for:

  • Asian Longhorned Beetle: This insect targets maple and other hardwood trees and is active during the summer and autumn months. These pests are especially destructive because trees can’t heal from the damage they inflict. The key sign they are attacking a tree is round exit holes about the size of a dime or smaller in the tree.
  • Emerald Ash Borer: These pests lay their eggs in the bark of ash trees, where they hatch and then burrow into the tree. They feed on the inner bark and phloem, creating S-shaped markings. As adults, they emerge from trees in spring, leaving D-shaped exit holes, and stay active until the end of summer.
  • Whitespotted Sawyer Beetle: These native wood-boring beetles are commonly found in Vermont. Adults emerge from circular exit holes in the wood and are active during the summer. They feed on conifers and lay their eggs in tender bark, where the larvae hatch. The larvae then bore into wood, creating girdling and dieback. You may see small piles of sawdust at the base of trees where larvae have been tunneling.
  • Elm Zigzag Sawfly: This destructive, invasive pest was confirmed for the first time in Vermont in 2023. It feeds on multiple elm species, creating zig-zag patterns on the leaves, and in high numbers full defoliation of trees can occur. Adult females emerge in late spring when the weather gets warm and lay eggs, which hatch into caterpillars that feed on the elm leaves. This is a new pest so methods for saving trees are still being explored. If caught early, trees can generally be restored to health.
  • Spongy Moth Caterpillars: In 2022, these invasive caterpillars defoliated almost 43,000 acres across Vermont. Also known as the Gypsy Moth, this pest feeds on the leaves of more than 300 species of trees and shrubs, eventually killing them. The larvae are active during May and June, and adults emerge in late June through mid-July and can persist into August. Most people have seen these brownish-gray caterpillars with tufts of hair at each segment. Mature larvae are between 1 ½ and 2 ½ inches long.
  • Hemlock Wooly Adelgid: Otherwise known as HWA, these pests feed on hemlock trees. These aphid-like creatures look like cotton balls at the base of tree needles and can cause yellowing needles, branch dieback, and more.
  • Spotted Lanternfly: These sap-feeding insects have yet to seriously infest Vermont, but have already had grave impacts in Massachusetts, Connecticut, Delaware, Maryland, and more. They can significantly harm vineyards and orchards by reducing photosynthesis through removing sap, as well as excreting a substance that allows a mold fungus to grow on plants. Spotted Lanternflies are known for being savvy hitchhikers at all stages of life. If you spot one of these bright inch-long insects, call a trusted Arborist immediately.
  • Bronze Birch Borer: These pests can be found on birch trees, though white, cutleaf, and yellow are preferred. They burrow within the bark of the tree as larvae during the winter and emerge from spring to August. Newly transplanted trees are at a particular risk as these pests cause infestation and branch dieback, especially when multiple galleries are present.

Call the Experts When You Suspect Tree Pest Infestations

If any trees on your property show signs of a pest infestation or just don’t look right, it’s important to call a skilled arborist. At Limbwalker Tree Service, our team of ISA Certified Arborists are experts at inspecting trees for insect damage and formulating an effective, targeted treatment method. Contact us today for a consultation and to learn more about our full range of tree services.

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