Cecropia Moths. Photo: JM
Identifying Moths
Irene Wilk


Each summer the Toronto Entomologists' Association holds a public Moth Night event in High Park in partnership with the High Park Nature Centre and High Park Nature.

An ongoing High Park Moth Study group have identified over 900 moths as of summer 2018. See Article in Ontario Insects, January 2019 and Article in Toronto Star, August 2019.

See also:

More about High Park Moth Night including consolidated sightings list.

Moth Gallery - photos of some of the moths that have been identified in High Park.

Mea skinnerella - 1st for Ontario (2015)
David Beadle

To learn more about moths:

Caterpillar sp.
Karen Yukich
Polyphemus Caterpillar (Antheraea polyphemus) one of our largest and most beautiful silk moths
Marius Locke
This uncommon and striking "micro" moth, Euclemensia bassettella, was spotted at the July 5, 2011 Moth Night.
David Beadle
Abott's Sphinx Caterpillar Feeds on grapeleaves, and marked to look like grapes!
Jon Hayes

Fall Cankerworm Moth (male)
Karen Yukich

Fall Cankerworm Moths

Fall Cankerworm (Alsophila pometaria), a native insect, can be one of the most damaging defoliators of Toronto’s urban forest. Members of this family are often called inchworms, loopers or spanworms, since the caterpillars loop when they walk.

Watch for the grey male moths in late fall when they fly in search of the flightless females waiting on tree trunks.

Tree banding in High Park's black oak savannahs by the City of Toronto and volunteers is an attempt to control the fall cankerworm population. Bands prevent female cankerworm moths from laying their eggs. Females are wingless. When they crawl up the tree they get trapped in the band's sticky resin, as do the winged males who fly in looking for mates. This will hopefully result in fewer cankerworms emerging in the spring, and put less stress on our black oaks.

See Banding Demonstration video

UPDATE January 2018

Relatively high numbers of Fall Cankerworm were caught on banding traps throughout the city and throughout High Park in fall 2017. This indicates that there will be a noticeable presence of Fall Cankerworm next spring and defoliation as well. Oak trees that were banded last fall should have a noticeable reduction in defoliation for the upcoming spring compared to non-banded trees.

Natural factors such as parasitism and mortality due to extreme cold may have an influence on populations of Fall Cankerworm but that remains to be seen. Other natural factors such as predators, nematodes, bacteria and viruses should also have an impact on Fall Cankerworm this season and help to collapse the population for upcoming years.

Approximately 20 to 30 trees in High Park will most likely be sprayed with a Btk based pesticide this spring to reduce some of the potential larvae. These trees are located to the sides of a walking trail running North/South, parallel to Parkside road, just south of the streetcar turnaround.

Provided by Forest Health Care, City of Toronto


City Fall Cankerworm Factsheet (pdf)


Gypsy Moths

Why are there so many dead gypsy moth caterpillars in some years? See US Factsheet

Karen Yukich

This introduced insect is a major pest in North America. The caterpillar (larva stage) eats the leaves of trees, making them more susceptible to disease and damage from other sources.

The City’s 2012 survey of egg masses suggested that some areas of Toronto would see severe defoliation in 2013. There are over 300 trees identified with high numbers of egg masses (>15). These were almost exclusively located in the manicured areas.

Gypsy Moth (female on egg mass)
Karen Yukich

Forestry conducted a gypsy moth control program in 2013 in High Park. Since aerial spraying could harm other moths and butterflies, a variety of control techniques were used instead.

The City's integrated control program includes vacuum removal of egg masses, ground spraying with Btk (a subspecies of a naturally-occurring bacterium Bacillus thuringiensis), and where necessary injection with TreeAzin.


Aerial spraying of Btk was used in High Park for the first time in spring 2019. There were two applications to a narrow area bordering the main north-south roads and part of one east-west road (see map and City of Toronto factsheet. As mentioned above, the broad use of Btk is a concern because other moths and butterflies (e.g. hairstreaks) have a similar occurrence and lifecycle. The Natural Environment Committee is in discussion with Forestry about this change in procedure.

See also: City Factsheet


Article in the News of the Lepidopterists' Society, Winter 2017 about recent immigrant moth species recorded in High Park and elsewhere.


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Content last modified on August 26, 2019, at 02:13 PM EST