Pest profile

Eastern Treehole Mosquito

Aedes triseriatus · Diptera: Culicidae[2]

The eastern treehole mosquito bites by day and is the primary vector of La Crosse virus.[1]

Eastern treehole mosquito, a dark mosquito with silvery white scale patches and unbanded dark legs, on weathered wood
Eastern treehole mosquito, a dark mosquito with silvery white scale patches and unbanded dark legs, on weathered wood. (c) Chris Baer, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • It's medium-sized and mostly dark, with silvery white scales, including narrow silvery stripes on top of the thorax.[1]
  • Unlike the yellow fever mosquito, its legs have no pale bands.[1]

Look-alikes

Look-alikeHow to tell them apart
Yellow fever mosquitoIts legs carry pale scale bands; the treehole mosquito's don't.[1]

Where it lives

It occurs across the eastern U.S. and parts of southeastern Canada, plus Cuba and northeastern Mexico.[1]

US map: public records from 24 states since 1990 (GBIF).

Biology and life cycle

Larvae develop in water-filled tree holes in hardwood forests and in discarded tires and plastic containers.[1]

Females can pass La Crosse virus to their offspring, which helps the virus survive winter.[1]

Health risk

La Crosse virus is the most common cause of pediatric arboviral encephalitis in North America, and children face the greatest risk of severe illness.[1]

Control

Sanitation

Control relies mainly on eliminating artificial containers that hold water.[1]

Common questions

Who is most at risk from La Crosse virus?
Children, who face the greatest risk of severe neurological complications.[1]
Does this mosquito bite during the day?
Yes; it's a daytime biter, and infections are most common in or near woods.[1]

Sources

  1. University of Florida IFAS Extension (Featured Creatures), “Eastern Treehole Mosquito, Aedes triseriatus (Featured Creatures).” edis.ifas.ufl.edu/publication/IN1473 (accessed 2026-10-06)
  2. iNaturalist, “Aedes triseriatus taxon page (order and family).” www.inaturalist.org/taxa/1112143 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.