West Nile Virus
Prevalence: Moderate
Risk 3/5
Asian Rock Mosquito
Ochlerotatus japonicus · “The Expanding Invader”
Small, dark mosquito recently introduced to North America from Asia. Adapts well to cold climates. Breeds in container water.
Disease risks
How to identify
- Size
- 4-6mm (small)
- Color
- Dark brown to black
- Distinctive features
- White markings on legs; palps without white tips
- Resting posture
- Head-down posture
- Prefers
- Humans and animals
- Pain level
- Moderate
- Persistence
- Persistent
- Transmission
- Competent vector for West Nile Virus
What actually works
Habitat Elimination (Source Control)
Removal and treatment of breeding sites. Professional inspection identifies and eliminates standing water where mosquitoes lay eggs.
Pyrethroid Spray Treatment
Professional-grade synthetic pyrethroid insecticide applied by licensed technicians. Fast-acting, EPA-approved, effective against adult mosquitoes.
Insect Growth Regulator (IGR)
Methoprene or pyriproxyfen application that prevents mosquito larvae from developing into adults. Chemical that mimics juvenile hormone.
Cities where Asian Rock Mosquito is active
New York, New YorkLong Island, New YorkPhiladelphia, PennsylvaniaWestchester, New YorkHempstead, New YorkBaltimore, MarylandBrookhaven, New YorkVirginia Beach, VirginiaIslip, New YorkPittsburgh, PennsylvaniaJersey City, New JerseyNewark, New JerseyBuffalo, New YorkNorfolk, VirginiaArlington, VirginiaRichmond, VirginiaRochester, New YorkBabylon, New York
Fun fact
Ochlerotatus japonicus survived introduction to North America only about 10 years ago but has rapidly spread throughout the Northeast, likely due to its cold-hardiness.