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How to identify it
- A sumac leaf rolled into a spiral and held with bands of silk, with neighboring leaves tethered to it; each caterpillar lives in a rolled leaf or between two leaves fastened together.[1][2]
- The caterpillar is greenish with small, obscure white markings and a whitish head, about half an inch long when mature; some individuals have a pale brown head and a green body striped with dark green.[1]
- The adult has a wing expanse of about 12 mm (half an inch) and is dull reddish or grayish brown mottled with darker patches, with fresh specimens sometimes tinged purple. Because many Episimus species look alike, a specialist may need the adult, and often its genitalia, to confirm the species.[2][1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Gold-striped leaftier | A pale green caterpillar with two faint whitish bands that feeds inside a single folded leaf of hardwoods such as birch, maple and oak, not in a spiral-rolled sumac leaf.[2] |
| Other sumac leaf feeders | UMass notes a long-standing question whether the caterpillars found on different host plants are all one species or a complex, and that adult moths are often required for identification.[1] |
Where it lives
Widely distributed; UMass describes it as a common species found through North and Central America, with records from New England, parts of Canada and Pennsylvania vineyards. Sumac is the preferred host, with witch-hazel, spurge and poison ivy also recorded.[1][2]
Biology and life cycle
Craighead (1950) reported two or more generations a year in parts of New England, with moths emerging in May and June and again from July to September; in parts of Canada emergence may occur only in late May and early June. The Forest Service likewise gives two or more generations.[1][2]
In a 1972 Pennsylvania trapping study, spring adults became active in late May, peaked in late June and early July and were done by July 11; the next generation's adults were trapped from late July, peaked in August and September and continued into October.[1]
The caterpillar rolls a leaf in a spiral, secures the rolls with silk bands, then joins neighboring leaves to the first and feeds inside. Caterpillars are present from June through late September in New England, and the insect overwinters as a pupa.[1][2]
Damage and signs
- The caterpillars roll, tie with silk and defoliate several species of sumac and the other hosts, with injury first appearing by June in Massachusetts. The feeding is not typically considered significantly detrimental to the overall health of the plant.[1]
- Partial feeding on the berries of winged sumac (Rhus copallina) has been recorded.[1]
Health risk
Neither source mentions any effect on people; the caterpillar feeds on sumac and related shrubs, including poison ivy.[1][2]
Control
Prevention
Management is typically not necessary. On ornamental sumacs, watch for rolled and tied leaves from June in Massachusetts; the moths are also attracted to grape berry moth pheromone and turn up in vineyard traps.[1]
Traps and physical control
Pinch tied leaves to kill the larva inside, or remove and destroy them.[1]
Biological control
Schaffner (1959) recorded tachinid flies (Actia species, Nemorilla floralis, Phorocera erecta), braconid and ichneumonid wasps (Meteorus trachynotus, Macrocentrus delicatus, Sambus hispae, Exochus pallipes, Labrorychus species) and the eulophid Dimmockia incongrua as parasitoids of this moth in New England.[1]
Pesticides
UMass lists Bacillus thuringiensis kurstaki, spinosad, acephate, azadirachtin, bifenthrin, carbaryl, clothianidin, deltamethrin, fenpropathrin, gamma- and lambda-cyhalothrin, neem oil, permethrin, pyrethrin plus sulfur and horticultural oil against the eggs as active ingredients labeled in Massachusetts; apply after bloom to protect pollinators.[1]
Common questions
- What rolled my sumac leaves into spirals?
- The sumac leaftier caterpillar, which rolls a leaf in a spiral, binds it with silk and then ties the neighboring leaves to it while it feeds inside.[1]
- Will it hurt the sumac?
- Not meaningfully. UMass says the feeding is not typically considered significantly detrimental to the plant's health and that management is usually unnecessary.[1]
- How many generations are there?
- Two or more a year in New England, with moths flying in May-June and again from July into September; in parts of Canada there may be only the spring flight.[1][2]
Sources
- UMass Extension Landscape, Nursery and Urban Forestry Program, University of Massachusetts Amherst, “Episimus argutanus, Sumac Leafroller (Sumac Leaftier), Insect & Mite Guide (Professional Guide for IPM in Trees and Shrubs).” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/episimus-argutanus (accessed 2026-11-10)
- USDA Forest Service, “Eastern Forest Insects, Miscellaneous Publication 1175 (W. L. Baker, 1972; scanned copy).” archive.org/details/easternforestins1175bake (accessed 2026-11-10)
- iNaturalist, “Episimus argutana taxon page (order and family).” www.inaturalist.org/taxa/357353 (accessed 2026-11-10)