Homeowners: Help Stop Gypsy Moth and Cankerworm

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The Town of Oakville is proposing to spend $205,000 on an aerial spraying program to combat gypsy moth and spring and fall cankerworm. Bacillus thuringiensis var. kurstaki (Btk) – a biological control agent – will be applied by low flying helicopter over 102.54 hectares of municipal woodlands in Spring 2018. More information on the municipal spraying program can be found here.

Homeowners can also take action to help stop gypsy moth and cankerworm from defoliating and harming their trees.

Adult female gypsy moth and egg mass. Flightless females emerge from their pupae in July and deposit hundreds of eggs in brown fuzzy egg masses. Egg masses remain on trees, rocks, and other surfaces over the winter. Caterpillars will begin to emerge in late April.

Act now! Here’s what you can do at home:

Scrape egg masses off trees anytime between now and next April to stop gypsy moth.

Locate egg masses: Gypsy moth (Lymantria dispar dispar) egg masses are usually 1-2 inches long and light brown and ‘fuzzy’. Egg masses can be found on tree trunks, in cracks, under peeling bark, and also on rocks, lawn furniture, sheds, garden pots, and behind shutters.

Physically remove egg masses: Use a putty knife or trowel to scrap eggs into a container and destroy the eggs by leaving them in soapy water for several days. Eggs scrapped onto the ground may still emerge in the spring, so it’s important to collect and destroy them.




  • Sticky bands around trees – April (targets emerging spring cankerworm and gypsy moth caterpillars) 
  • Pheromone traps to catch adult male gypsy moth – July/August 
  • Burlap banding to catch gypsy moth caterpillars – July to September 
  • Sticky bands around trees  – October to November (targets female adult cankerworm moths before they lay eggs)

Applying sticky bands next April will help catch emerging Spring Cankerworm (Paleacrita vernata) and gypsy moth caterpillars. Sticky bands applied in October and November trap flightless adult female Fall Cankerworm (Alsophila pometaria) as they travel up the tree to lay eggs. Scraping gypsy moth egg masses now and preventing females from laying eggs on your trees next year, reduces the number of hungry caterpillars emerging the following spring.

Fall Cankerworm egg mass on birch.
Fall cankerworm female moth on white birch.
Fall cankerworm eggs are very small…

Watch the City of Toronto Forestry’s How to Video on how to make and install a sticky band using Tree TanglefootTM (available at most hardware stores or garden centres).


A diverse mix of trees, shrubs and herbaceous plants in your neighbourhood and backyard – also known as ‘backyard biodiversity’ – helps to support the native birds, insects, small mammals and amphibians that feed on gypsy moth and cankerworm caterpillars, eggs and pupae. Support biodiversity on your property and the birds, bees and critters will help to keep the gypsy moth and other damaging insects in check. Check out this ‘Natural Enemies of Gypsy Moth:  The Good Guys’ resource from MSU Extension.

More information available from Conservation Halton and the Hamilton Conservation Authority.