Family: Chrysomelidae
Subfamily: Galerucinae
Length: 5-6.5 mm
Disonycha is a large genus, with 35 species in America north of Mexico, 16 species in the northeast, and at least 11 reported from West Virginia. Disonycha can be hard to identify to species.
As the common name implies, these beetles can really jump. Flea beetles are the bane of gardeners, because they make numerous unsightly holes on a leaf, making it look as if the leaf has been hit with buckshot. The damage caused by the beetles can lead directly to low crop yields.
Disonycha pensylvanica, however, is not a pest of crops or gardens, and is most often encountered in wetlands where it feeds on plants in the genus Polygonum.
Traits to look for on the Pennsylvania Flea Beetle: A black head, a black scutellum, and legs reddish to black. The pronotum is yellowish to reddish with a large, dark central spot. The pale markings on the elytra are as seen in the photo. Females of Disonycha pensylvanica have costate (ridged) elytra.
Note that the scientific name for this species is sometimes misspelled pennsylvanica, but pensylvanica is correct.
