Annual spring mosquito control campaign to combat mosquitoes begins

The Delaware Department of Natural Resources and Environmental Control (DNREC) is set to begin its annual spring mosquito control campaign next week, aiming to reduce the emergence of mosquitoes in the state.

Starting as early as Tuesday, March 18, DNREC’s Mosquito Control Section will begin spraying woodland pools to target aquatic mosquito larvae before they develop into adult mosquitoes later in the spring.

The campaign will begin in southern Sussex County and expand across Kent and New Castle counties over the coming weeks, depending on weather conditions.

The early-season spraying targets larvae in woodland pools, a common breeding ground for mosquitoes, which helps prevent the emergence of adult mosquitoes in the area, typically seen in early May.

DNREC plans to treat up to 10,000 acres of wet woodlands, especially near populated areas.

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However, due to ongoing drought conditions across

Delaware, the amount of water in these woodlands is significantly lower than usual. Despite the reduced water levels, the Mosquito Control Section will continue its efforts using a helicopter to apply Bti (Bacillus thuringiensis israelensis), a bacteria-derived insecticide known for its effectiveness in controlling mosquito larvae. The U.S. Environmental Protection Agency (EPA) has approved Bti for use in mosquito control, deeming it safe for humans, wildlife, and the environment when applied as directed.

This campaign marks the start of Delaware’s mosquito control season, which typically extends until late October or early November. As the season progresses, efforts will shift to controlling other mosquito species, including saltmarsh mosquitoes and container-breeding mosquitoes found in urban and suburban areas. These efforts are vital in reducing mosquito populations and safeguarding public health, particularly as mosquitoes are known to carry diseases like West Nile virus and Eastern Equine Encephalitis.

Residents can stay informed about scheduled mosquito spraying by calling DNREC’s toll-free line at 800-338-8181. Additionally, the public can subscribe to the Mosquito Control Spray Zone Notification System for updates via email, text, or voicemail at de.gov/mosquitospray.