Alsophila pometaria, the fall cankerworm, is a lepidopteran pest of hardwood and shade trees, and is native to North America. The larvae (caterpillars) commonly feed on ash, basswood, beech, black cherry, red maple, sugar maple, red oak, and white oak, but will also eat apple, birch, boxelder, dogwood, elm, hickory, and many other hardwoods. The adults are active in the fall, usually emerging from their pupal phase in October to lay orderly clusters of about 100 eggs lined up in neat rows, which overwinter on the small twigs to which they adhered. This lifecycle differentiates the fall cankerworm from the very similar but less common spring cankerworm, Paleacrita vernata, which overwinters as a pupa and is active as an adult to mate and lay eggs in the spring. Both cankerworms feed on the same trees and have overlapping ranges. Population numbers of fall cankerworm naturally fluctuate and reach populations large abundance every 15-20 years. While outbreaks of cankerworms, which last several years, can defoliate trees, healthy trees usually recover without significant damage even when attacked for two years in a row. In outbreaks cankerworms are seen as a nuisance in public areas when in late summer the larvae (small green caterpillars known as loopers or inchworms) drop from trees on silk webs in large numbers on their way to finding spots to pupate, and then again as the adult moths climb buildings to lay their eggs. While adult male moths are grayish-brown with a wingspan of about three centimeters, female moths are wingless, and look more like a spider than a moth.

(Ascerno and Hanh, 2003; Hoover and Haydt, 2010)

Males have an even brownish grey forewing with jagged white and dark PM and AM lines, occasionally with a visible dark discal spot. The hindwings are light grey, with a dark discal spot and a faint pale PM line. The females are wingless and stout-bodied, looking very unlike a lepidopteran.

Nova Scotia west to Alberta, south to Colorado and California (McGuffin 1988). In Saskatchewan and Alberta, this species is associated with Manitoba Maple shelter belts in the southern parts of the province. It did not occur historically in the Edmonton region, but is now established here and is often common in October on city Elm trees.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Wooded areas including city parks, ornamental plantations and shelter belts.

Larvae feed on a large variety of deciduous trees and shrubs, especially elm (Ulmus spp.), ash (Fraxinus spp.), and maple (Acer spp.), which are non-native to Alberta but often planted in cities and as shelterbelts.

Adults fly after the first fall frosts have occured, peaking in mid October.

The larvae are often a serious pest of many tree species elsewhere, although it rarely reaches densities high enough to do damage in Alberta. The eggs are laid in clusters on tree branches and trunks by the wingless females and hatch the following spring, synchronized with the flush of leaves. There are four larval stages, which are described in detail by McGuffin (1988). Larvae pupate in the soil and delay their emergence until fall, spending about four summer months as a pupa. Females in at least some populations are able to reproduce parthenogenetically (without mating). (McGuffin 1988).

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 25 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

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Barcode of Life Data Systems (BOLDS) Stats
Public Records: 25
Species: 38
Species With Barcodes: 1

No concern; often reaching pest status.

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: NNR - Unranked

Rounded Global Status Rank: GNR - Not Yet Ranked