Elm-pest
Guides
Aceria parulmi
Elm Finger Gall Mite
Aceria parulmi is an eriophyid mite species commonly known as the Elm Finger Gall Mite. It is a plant-parasitic mite that induces distinctive gall-like structures on elm leaves. Like other members of the genus Aceria, it has a worm-like, elongated body with four legs and is extremely small, typically less than 0.2 mm in length. The mite is specialized to feed on elm species (Ulmus), causing characteristic finger-shaped galls on leaf surfaces.
Corythucha ulmi
elm lace bug
Corythucha ulmi, the elm lace bug, is a species of lace bug in the family Tingidae. It is native to North America and feeds on elm trees (Ulmus spp.). Like other lace bugs, it is a small sap-sucking insect that causes characteristic white stippling damage on leaves. The species was described by Drake in 1916.
Kaltenbachiella ulmifusa
Slippery Elm Gall Aphid
Kaltenbachiella ulmifusa, commonly known as the Slippery Elm Gall Aphid, is a gall-forming aphid species in the family Aphididae. It induces distinctive galls on elm trees (Ulmus spp.), particularly on slippery elm (Ulmus rubra). The species is native to North America and has been documented primarily in the eastern and central United States. Like other members of the subfamily Eriosomatinae, it exhibits a complex life cycle involving host alternation.
Monocesta
larger elm leaf beetle
Monocesta is a genus of skeletonizing leaf beetles in the family Chrysomelidae. The genus contains at least three described species, with Monocesta coryli being the most well-known and commonly encountered in eastern North America. These beetles are characterized by their feeding behavior that removes soft leaf tissue between veins, creating a distinctive skeletonized appearance on host leaves. The genus is primarily associated with elm trees and related woodland vegetation.
Orchestes
flea weevils
Orchestes is a genus of flea weevils (Curculionidae) comprising six species in North America and additional species in Eurasia. Members are small beetles (2–4 mm) associated with woody host plants, particularly trees in Ulmaceae and Fagaceae. The genus was historically confused with Rhynchaenus, from which it has been redefined. Several species are significant pests: O. steppensis is a destructive invasive of elms in China and North America, O. alni (European elm flea weevil) damages elms in Europe and North America, and O. fagi attacks beech trees. Larval habits vary—most are leaf miners, though O. hustachei uniquely parasitizes aphid galls.
Orchestes steppensis
European Elm Flea Weevil, Elm Flea Weevil
Orchestes steppensis is a small flea-weevil (2.6–3.2 mm) native to the Eastern Palaearctic Steppe region and now invasive in North America. It is a serious pest of elm trees (Ulmus spp.), with adults feeding on leaves and larvae mining leaf tissue. The species was previously misidentified as O. alni or O. mutabilis in China. It completes one generation per year in Xinjiang, China, with overwintering adults emerging in late March to early April. The species exhibits strong olfactory-mediated host location, with documented preferences for specific plant volatiles.
Physocnemum
elm bark borer
Physocnemum is a small genus of longhorned beetles (family Cerambycidae) containing three described species found in North America. The genus is characterized by ant- and wasp-mimicking appearance, with dark bodies, small amounts of red coloration, and polished ivory-colored ridges at mid-elytra that create the illusion of a narrow waist. The most well-known species, P. brevilineum (elm bark borer), develops in the bark of living elm trees and has been documented as an occasional pest causing injury to inner bark and cambium. Other species include P. andreae (cypress bark borer) and P. violaceipenne.
Physocnemum brevilineum
Elm Bark Borer
A small, wasp-mimicking longhorned beetle commonly known as the elm bark borer. Adults are dark with reddish accents and possess polished ivory-colored longitudinal ridges at mid-elytra that create the illusion of a narrow wasp waist. The species is considered uncommon despite having a common name and documented pest status. Larvae typically mine within the bark of living elm trees but have been observed in recently dead trees as well, occasionally causing injury to inner bark and cambium.
Saperda tridentata
elm borer
Saperda tridentata, commonly known as the elm borer, is a longhorn beetle (Cerambycidae) native to North America. The species was described by Guillaume-Antoine Olivier in 1795. It is notable for its specialized association with elm species (Ulmus), serving as both a direct pest and a vector of Dutch elm disease. The beetle's life cycle involves larval tunneling in cambium and sapwood, creating characteristic U-shaped galleries. It also acts as a host for the parasitoid wasp Cenocoelius saperdae.