Preventive control of forest tent caterpillars: you can do your part!

Apr 24, 2025

Summer will soon be here, and the trees will be full of leaves again. Before the leaves begin to bloom, it's the perfect time to inspect your small trees and shrubs around your home and remove forest tent caterpillar eggs. For the past two years, forest tent caterpillars (Malacosoma disstria) have invaded several deciduous trees in our community, causing significant foliage damage and several inconveniences for residents.

Trees have reserves and can produce new leaves during the summer. However, if a tree is repeatedly defoliated over a few years, it could suffer irreversible consequences and eventually die. The good news: it is possible to take preventive action now to limit the appearance of forest tent caterpillars in your home. As the season begins, here are some tips for easy and effective control:

How to spot the eggs?

• They appear as small, grayish-brown sleeves, stuck around young twigs
• They are mainly found on trees such as poplars, birches, cherries, apple trees, maples, etc.
• These eggs were laid at the end of last summer and spent the winter there, ready to hatch in the spring

How to remove them?

1. Wear gloves, even if the eggs don't sting.
2. Inspect your trees, especially the branches at eye level
3. Scrape or prune the twigs containing eggs using a tool (knife, pruning shears)
4. Place the eggs in a sealed plastic bag and throw it in the trash.
5. Avoid leaving the eggs on the ground, as the caterpillars could still hatch

By removing the eggs...

• You protect your trees from premature defoliation
• You reduce the spread in your neighborhood
• You limit the nuisance caused by stinging caterpillars later in the season

Please note that even if everyone does their part to remove the eggs, it is very likely that forest tent caterpillars will appear in certain areas of the municipality. It is important to remember that this is a native species that represents a temporary aesthetic problem. This is not an environmental problem; the trees will regrow leaves, and the caterpillars will eventually disappear.

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CONTACT: Daniel Gautreau, Green Spaces Coordinator, Public Works Department, 506.739-2103, daniel.gautreau@edmundston.ca