Numbers
the only species in this genus in North America
Identification
Adult: forewing light tan or pale brown with irregular patches of white, a white crescent along inner edge, and several black longitudinal streaks in the subterminal area; hindwing brownish-white; thorax has double crest
Mature larva: pearly-white to bluish-white background, numerous black lateral spots, five yellow stripes, and two broad broken black lines along the back
Range
southeastern Canada and northeastern US at least to Maryland, plus northwestern US and British Columbia - range expanding in some areas
native to Europe, western Asia, and northern Africa
Habitat
pastures, agricultural fields, roadsides, waste places where host plant grows
Season
adults fly from May to August
larvae present from early summer through fall
Food
first and second instar larvae feed on the flowers, and later instar larvae feed on the leaves of Toadflax (Linaria spp.)
adults nectar on flowers of Toadflax and other plants
Life Cycle
adults emerge from May to August and lay 100-400 eggs singly on both leaf surfaces of host plant; eggs hatch in about 7 days, beginning in early summer; larvae feed from early summer through fall, and overwinter in pupa stage usually in/on the soil or sometimes on stem of host plant; two overlapping generations per year in Ontario, one to three generations elsewhere
Remarks
First released in Canada (1,500 larvae) in 1962 at Belleville, Ontario; subsequent releases in Nova Scotia; now established in ON QC NB NS, and spreading south in the US at least to Maryland.
First released in the US in 1968 near Missoula, Montana; subsequent releases in Arizona, Colorado, Idaho, Montana, Oregon, Washington, and Wyoming; now established in Idaho, Montana, Washington, plus southern British Columbia.
Larvae defoliate about 20 percent of Yellow Toadflax stems in Ontario but do not reduce plant density.
Internet References
live larva image on host plant (Gary Piper, Washington State U.)
live adult and larva images from Italy and Russia (Moths and Butterflies of Europe & North Africa)
