Episimus argutana (Clemens) (Tortricidae: Olethreutinae: Olethreutini)
Common names: sumac leaftier moth
Synonyms: allutana (Grapholitha), hamameliella (Catastega)
FWL: 4.5–6.0 mm (males); 5.0–7.0 mm (females)
Head, thorax intermixed with red-orange, chalky blue, and pale yellow scales; forewing heavily mottled with pale yellow, red-orange, black, and chalky blue scaling; ocellus well-developed and represented by elongate black dots; costal strigulae present as small white paired lines, often filled or suffused with chalky blue scaling; fringe bicolored: gray on apical half, pale yellow on tornal half; male without forewing costal fold; hindwing brown.
Male genitalia are characterized by a narrow, pointed uncus; long, narrow valvae with a ventral lobe at the distal end of the sacculus; and a poorly differentiated cucullus. Female genitalia are characterized by a moderate, quadrate signum; a minute ring of sclerites present at the base of the corpus bursae; and two small, thorn-like signa.
The following account is summarized from MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..
Mature larvae 10–12 mm in length; width of head approximately 0.9 mm; head pale, with darker lateral pigmentation; prothoracic shield, legs, body, and anal shield pale yellow; body sometimes with faint reddish pigmentation; anal fork present, poorly developed; SV group on A1, 2, 7, 8, 9 usually 3:3:3:2:2.
A complete description of larval chaetotaxy is a available in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..
Several species of Episimus are similar to E. argutana, but only other widespread species in North America is E. tyrius Heinrich, which primarily feeds on maple (Acer spp.). It can be identified by its reddish-purple forewing coloration and narrower cucullus in the male genitalia compared to E. argutana.
Episimus argutana is broadly distributed in North America, from Nova Scotia to British Columbia and south to Florida, Texas, and southern California. It is apparently absent from the Rocky Mountains. No records of this species are known from Mexico, although there are several similar species which do occur there.
Little is known about the biology of Episimus argutana beyond host records. Larvae tend to twist or fold a single leaf of a young host plant leaf and feed by skeletonizing the leaf while living in the folded shelter. Adults can be found nearly year-round in the southernmost portion of its range, but have a more restricted flight period (May to September further north). There are at least two generations per year in the north, and three or more in Florida and Texas.
The preferred host appears to be members of the Anacardiaceae, especially sumac (Rhus spp.) and poison ivy (Toxicodendron spp.), but E. argutana is also commonly reared from witch-hazel (Hamamelis virginiana). Other host records are known, but several of these are dubious and require verification (i.e., Alnus, Betulus, Crataegus, Sambucus, Solidago).
View full screen host table here
Authors: KA Austin, TM Gilligan, ME Epstein
Content last updated May 2025
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