Northern House Mosquito Identification & Control

Quick Identification

• Size: About ¼ inch long
• Color: Dull brown with lighter banding on abdomen
• Key Features: The most common mosquito species in Illinois; breeds in standing water; primarily active at dawn and dusk
• Active Season: Late spring through fall (May–October in Will County)
• Risk Level: High — primary vector of West Nile virus in Illinois

The West Nile Virus Mosquito

The northern house mosquito is the primary carrier of West Nile virus in Illinois, and Will and DuPage counties regularly report positive mosquito samples during summer surveillance. While most mosquito bites cause only itching and irritation, West Nile virus can cause serious illness — particularly in older adults and people with compromised immune systems. In severe cases, the virus can cause neurological disease including encephalitis and meningitis.

This species breeds prolifically in standing water. A single female can lay hundreds of eggs in as little as a bottle cap of stagnant water. Clogged gutters, birdbaths, flower pot saucers, tire swings, low spots in yards, and retention ponds all become breeding sites. Properties near the DuPage River corridor, retention pond systems in Carillon and Grande Park, and the newer subdivisions along 143rd Street face particularly heavy mosquito pressure.

Northern house mosquitoes are primarily crepuscular — most active at dawn and dusk. If mosquitoes are driving you indoors during the best hours of summer evenings, your property has a mosquito population that won’t resolve on its own. Professional barrier treatments target the shaded resting areas where mosquitoes hide during the day and the conditions that support breeding. Contact Sanctuary Pest Control at 815-993-3472 for mosquito assessment and seasonal treatment.