On this page
How to identify it
- The overwintering females are about 2 mm long, brown and oystershell shaped, with grayish margins and orange-yellow shed skins at the narrow end; the body under the cover is white. The cover is straight unless the scales are crowded. Male covers are shorter, about 1 mm, and orange-brown.[1][2]
- On winged euonymus the scales sit mostly on twigs between the bark ridges that form the wings; only in heavy infestations do they spread onto leaves near the midveins.[1]
- Eggs and crawlers are white. From late July into August every stage can be found at once, from eggs under the female covers to settled young scales.[1][2]
- It occurs only on deciduous hosts. Scales on an evergreen euonymus are some other species, most often euonymus scale.[1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Euonymus scale | Euonymus scale (Unaspis euonymi) is a different species that is also found on Euonymus, including the evergreen kinds; the fire bush scale is never found on evergreen euonymus and on burning bush sits mostly between the bark wings of the twigs.[1] |
| Oystershell scale | The fire bush scale is in the same genus as oystershell scale and shares the brown, oystershell shape, which is why it is also called the yanagicola oystershell scale; ScaleNet notes it is extremely close to Lepidosaphes corni and is separated on microscopic characters of the rear end of the body.[1][2] |
| Glover scale | Glover scale (Lepidosaphes gloverii) can occur on euonymus but is mainly a citrus pest; separating the two takes slide-mounted specimens and a scale taxonomist.[1] |
Where it lives
Reported from Georgia, Indiana, Maryland, Massachusetts, Missouri, New Jersey, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Virginia and West Virginia, and native to East Asia (China, Japan, Russia and South Korea).[1][2]
Biology and life cycle
UMass lists alder, elm, linden, maple, pachysandra, persimmon, silk tree, willow and winged euonymus as hosts; ScaleNet records 21 host genera including dogwood, mulberry, ash, lilac, poplar, black locust, walnut and camellia, and Euonymus alatus, E. fortunei and E. japonicus.[1][2]
One generation a year. Fertilized adult females overwinter on the twigs and begin laying eggs in mid-June in Pennsylvania, continuing for nearly a month. Crawlers appear by about June 20 in Ohio, in June in Maryland and, historically, mid-to-late July in Massachusetts.[1][2]
Because egg laying is spread over a month, all life stages are present from late July into August. The young scales mature and mate before frost; by the time cold weather arrives the males have died and only fertilized females remain to overwinter.[1][2]
Two tiny parasitic wasps, Alaptus auranti and Alaptus pallidicornis, are recorded as natural enemies.[1]
Damage and signs
- Heavy infestations cause premature leaf drop, twig dieback and greater susceptibility to winter injury. Such damage has been seen on euonymus in Maryland, in Ohio nurseries and on winged euonymus in nurseries across the northeastern United States.[1][2]
- Its status varies by place: ScaleNet calls it an occasional pest, and in Pennsylvania heavy populations on burning bush rarely cause visible damage.[2][1]
Health risk
Neither source mentions any effect on people or pets; the only harm described is to the host plant.[1][2]
Control
Prevention
Look for the scales in fall and the dormant season, inspecting stems closely and especially between the bark ridges of winged euonymus, so that heavily infested stems can be pruned before eggs hatch. Infestations often go unnoticed until leaves are off-color or dropping early.[1]
Traps and physical control
If only a few branches are infested, prune them out and remove them, ideally before crawlers emerge in June or July.[1]
Biological control
Two parasitic wasps of the genus Alaptus attack this scale; their effectiveness is not described, so do not count on them alone for a heavy infestation.[1]
Pesticides
Massachusetts lists horticultural oil, insecticidal soap, neem oil, azadirachtin, pyriproxyfen, buprofezin and systemic active ingredients such as acetamiprid, dinotefuran and imidacloprid among the materials labeled for this scale on landscape trees and shrubs; time contact sprays to the crawler stage, which runs from June into August depending on the state.[1]
When to call a professional
A heavily infested hedge of mature burning bush, or a large linden or maple, is a job for an arborist who can confirm the species and choose a crawler-timed or systemic treatment.[1]
Common questions
- Is this the same thing as euonymus scale?
- No. Euonymus scale (Unaspis euonymi) is a different species that also attacks evergreen euonymus. The fire bush scale is found only on deciduous hosts, and on burning bush it hides between the bark wings of the twigs.[1]
- When are the crawlers out?
- Egg laying starts in mid-June in Pennsylvania and runs about a month. Crawlers have been recorded by late June in Ohio, in June in Maryland and in mid-to-late July in Massachusetts, and all stages are present from late July into August.[1][2]
- Will it kill my burning bush?
- Heavy infestations can cause early leaf drop, twig dieback and winter injury, and have damaged nursery plants in Ohio and the Northeast. In Pennsylvania, though, large populations rarely cause visible harm. Pruning out the worst branches before egg hatch usually keeps it in check.[1][2]
Sources
- UMass Extension Landscape, Nursery and Urban Forestry Program, “Lepidosaphes yanagicola (scale on Euonymus alatus, fire bush scale), Professional Insect & Mite Management Guide for Woody Plants.” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/lepidosaphes-yanagicola (accessed 2026-11-10)
- ScaleNet (scale insect database begun at the USDA ARS Systematic Entomology Laboratory), “ScaleNet catalogue: Lepidosaphes yanagicola Kuwana, 1925.” scalenet.info/catalogue/Lepidosaphes%20yanagicola/ (accessed 2026-11-10)
- iNaturalist, “Lepidosaphes yanagicola taxon page (order and family).” www.inaturalist.org/taxa/1617412 (accessed 2026-11-10)