Paleacrita vernata
(Peck, 1795)
Spring Cankerworm, Spring Cankerworm Moth
Paleacrita vernata is a geometrid known as the spring cankerworm. Males have functional wings and fly from February to late May, while females are wingless and climb tree trunks to lay . The larvae are defoliators of deciduous trees and shrubs, with documented feeding on Acer, Ulmus, Betula, Prunus, and Quercus . The species has been observed using flax as a secondary , indicating broader host flexibility than previously recognized.
Pronunciation
How to pronounce Paleacrita vernata: //pæliːˈækrɪtə vɜrˈneɪtə//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Males have forewings 11–18 mm in length; females are wingless and must climb vegetation to reach -laying sites. Males fly in late winter and early spring, distinguishing them from the related fall cankerworm (Alsophila pometaria), which emerges in autumn.
Images
Habitat
Deciduous forests and woodlands; agricultural areas where cultivated flax is present; urban and suburban environments with ornamental and native hardwood trees.
Distribution
North America from the Atlantic Ocean west to Alberta, Texas, and California. Documented in Canadian provinces including Alberta, Manitoba, and Saskatchewan, and in the northeastern United States.
Seasonality
males active from February to late May. Winter and early spring ; larvae present following hatch in spring.
Diet
Larvae feed on leaves of various deciduous trees and shrubs, especially Acer, Ulmus, Betula, and Prunus . Oaks (Quercus) are also affected. Has been documented feeding on flax (Linum usitatissimum) as a secondary .
Life Cycle
Females climb tree trunks to lay . Eggs hatch into larvae that feed on foliage. First instar larvae disperse using silk threads that catch wind, allowing aerial transport to host plants. occurs in soil; emerge the following late winter or early spring. One per year.
Behavior
Larvae descend from the on silk threads when disturbed and can climb back up these threads. Homeowners use sticky bands around tree trunks to intercept climbing wingless females before -laying.
Ecological Role
Defoliator of deciduous trees; can cause significant tree damage during years. Serves as prey for various and .
Human Relevance
Considered an occasional pest of ornamental and forest trees. Sticky band traps are used as a control measure. Documented as a potential pest of flax .
Similar Taxa
- Alsophila pometaria (Fall Cankerworm)Also has wingless females and similar larval , but emerges in autumn rather than late winter/spring.
- Phigalia strigataria (Small Phigalia)Nearly identical , geographic range, and temporal distribution; also has wingless females and wind-dispersing first instar larvae.