Length: typically 3.25-3.75 mm
More than 200 species of Empoasca live in America North of Mexico, and a good many of them are found in West Virginia. Most are slender and green, small as planthoppers go, though not miniscule.
A number of members of this genus are agricultural pests, including the Potato Leafhopper, Empoasca fabae, which damages a variety of crops in the Mountain State.
Empoasca fabae are not cold tolerant, and cannot overwinter in West Virginia. Each year the species invades the Mountain State anew, part of an "aeroplankton" that rides the wind currents north from the Deep South.
Researchers at the University of Pennsylvania were interested in the leafhoppers return trip south, and in 1981 and 1982 they monitored Empoasca fabae at a height of 152 meters, using nets mounted to an airplane. On one particular day the researchers noted a huge cloud of E. fabae "headed in the direction of West Virginia" and they predicted these leafhoppers would have arrived there by the next morning. Details of the return flight to Georgia and other points to the South are still not clear and this migration merits further study.
Left: a majority of Empoasca species are pale green with pale markings, or are essentially unmarked.
In a study of ten Pin Oak trees in Kentucky during three growing seasons, researchers caught 7,903 Empoasca leafhoppers, making up 25.0% of the total leafhopper capture. In most cases, the Empoasca preferred to live in the top of the Pin Oak canopy (Johnson and Freytag, 2001).
Empoasca species are typically broader at the front, and taper toward the rear.
Young (1952) commented that in the forewings of genus Empoasca, "venation [is] quite variable interspecifically and intraspecifically, often somewhat variable between [the] two wings of the same specimen."
Young shared the observation of Paul Christian, that Empoasca hoppers almost always have some green coloration on the legs, a trait that can help separate Empoasca from similar genera in the field.
Identification of Empoasca to species can be a real challenge; Young summed it up by observing, "the genus is a large and difficult one."
Insects of West Virginia