Worcester’s tentative West Nile spraying dates begin August 4

Worcester’s next tentative mosquito-spraying date is Tuesday, August 4, two days away, after West Nile virus was detected in mosquitoes collected from a trap site in the city.

The city also lists tentative truck-mounted applications for August 11, 18 and 25, 2026. Worcester says its current West Nile virus risk level remains low, and the dates and locations can change.

What Worcester reported

The Massachusetts Department of Public Health notified Worcester that a mosquito sample collected from a city trap tested positive for West Nile virus. That result concerns mosquitoes; it does not establish a human infection.

The city’s July 21 notice said truck-mounted pesticide applications were scheduled for the general area connected to the positive sample, with additional tentative Worcester dates planned for August. The response is being carried out through the Central Massachusetts Mosquito Control Project.

Dates and locations can change

The tentative Worcester dates are August 4, 11, 18 and 25, 2026. CMMCP says its schedules are subject to weather and current mosquito populations. Worcester also lists mosquito-virus activity and special-event spraying as reasons the dates or locations may be adjusted.

Residents should not assume that every Worcester neighborhood will be treated. CMMCP posts the scheduled spray areas each day, and residents should use the applicable area map and daily posting to determine whether their location is included.

CMMCP says tentative spray areas are posted on its website and on its phone system after 3:30 p.m. each day. Call 508-393-3055 and press 0 to hear the recorded message.

What residents should do

If an area is scheduled for treatment, residents should close street-facing windows and turn off any “outside air” settings on air conditioners. People should remain indoors during the application and for 15 to 20 minutes afterward.

Pets should be kept inside between sunset and midnight. Children should not play near or behind truck-mounted applicators while they are operating. Home-garden vegetables should be washed after spraying and before they are eaten.

Residents can receive notifications about specific areas and neighborhoods through ALERTWorcester by registering with a current email address or phone number. The city says additional alerts may be issued if mosquito-borne illness is detected and emergency spraying becomes necessary.

Property exclusions

Residents who want to exclude their property from a wide-area pesticide application must follow the Massachusetts state process for requesting an exclusion or opt-out. Worcester directs residents to that state procedure rather than handling property exclusions locally.

Reducing mosquito exposure

Worcester recommends limiting mosquito exposure by wearing long sleeves and pants when possible, using insect repellent according to its label, avoiding mosquito activity around dawn and dusk, and draining standing water from containers and other areas around the home.

Before August 4, residents should check the latest CMMCP spray-area posting and the applicable map. The August schedule remains tentative, and the date, time and location may change.

Sources

• City of Worcester: West Nile Virus Detected, Spraying Scheduled for Thursday
• Central Massachusetts Mosquito Control Project: 2026 Spray Schedules
• Massachusetts Department of Public Health: West Nile virus information
• WBUR: West Nile detected in Worcester