What is Spongy Moth?

Spongy moth is the insect formerly known as gypsy moth. In the caterpillar phase of its life cycle, they eat the leaves of trees that they have infested. Ottawa is currently in the midst of an outbreak of Spongy Moth. Residents can help to contain and limit the damage to trees caused by Spongy Moths.

Spongy Moth Actions

Report spongy moth sightings

Residents can report spongy moth sightings using the City’s online reporting tool(link is external). Input received from residents helps to inform and coordinate monitoring efforts across Ottawa. City staff can use the information collected to supplement the City’s egg mass surveys, conducted during the fall and winter seasons, and to determine the level of the infestation in specific areas of the city.

Egg mass removal (August to May)

Survey your property for egg masses and scrape them off surfaces into soapy water to destroy them.

Btk application (May to June)

Btk (Bacillus thuringiensis kurstaki) is a biopesticide available for purchase from local hardware stores to use against spongy moth. This product affects the caterpillars’ digestive system and should only be applied between May and early June when spongy moths are still in the larval (caterpillar) stage.

Hand pick caterpillars (May to July)

Handpicking caterpillars is most effective on small newly planted trees, shrubs, and plants infested with spongy moth. If possible, gently shake the tree so caterpillars fall from leaves. Thoroughly inspect the remaining foliage, branches, and trunk for caterpillars. Wearing gloves, pick them off your tree. Fallen and collected caterpillars should be placed and left to soak in soapy water to destroy them. Caution: the caterpillars have long hairs that can cause skin irritation, so it is recommended to wear long-sleeves and gloves.

Burlap banding (May to September)

By mid-June, spongy moth caterpillars will grow to about 2.5 cm in length and move down tree trunks. Residents can help to reduce the number of caterpillars on trees by trapping them with burlap. Burlap banding can be folded in half and attached to tree trunks using a string around the trunk. Caterpillars will congregate in the burlap, which can be removed and disposed of in the City’s curbside collection.


Spongy Moth Fact Sheet 2022

Egg Mass Scraping Fact Sheet

Burlap Installation Fact Sheet

Spongy Moth Fact Sheet – French 2022

Additional information about the Spongy Moth is available on the City of Ottawa website.

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