About Enargia decolor Walker, 1859
Enargia decolor, commonly known as the pale enargia or aspen twoleaf tier, is a moth species belonging to the family Noctuidae. It has a boreal-transcontinental distribution across the Canadian boreal plain, extending southward through higher elevations of the western cordillera. Its range is thought to be limited by the presence of trembling aspen and potentially other poplar species. Confirmed records extend from the northernmost region of British Columbia and southwestern Northwest Territories east to New Brunswick. It has also been reported from Nova Scotia, Ohio, and New York. In the western United States, it has been documented in western Montana, Idaho, Washington, Oregon, Nevada, Utah, Wyoming (Albany and Carbon counties), western Colorado, New Mexico (Grant County), and Arizona (Graham County). No records exist from the Rocky Mountain front ranges of Colorado, where the species would be expected to be widespread if it had a continuous distribution extending south into New Mexico and Arizona. Populations located west of the Rocky Mountains as far south as New Mexico and Arizona may represent a separate distinct species. The wingspan of Enargia decolor ranges from 30 to 40 mm. Adult moths are active in flight from late July to early September, with most sightings recorded after mid-August. Larvae have been observed feeding on Betula papyrifera, Populus balsamifera, Salix species, Populus grandidentata, and Alnus rugosa. In boreal forest regions, larval populations can reach levels high enough to cause extensive defoliation of stands of Populus tremuloides (trembling aspen).
