The Cumberland County Vector Control Office will conduct an ultra-low volume (ULV) mosquito control operation on Thursday, July 23, 2026, from dusk (approximately 8:00 PM) until 11:00 PM.
The truck-mounted treatment will target specific residential and recreational areas in North Middleton Township and South Middleton Township. If weather conditions prevent application tonight, a backup spray date is scheduled for the following evening.
The localized treatment comes in response to routine surveillance by county public health technicians, which revealed multiple adult mosquito samples testing positive for West Nile Virus (WNV) alongside elevated overall mosquito populations in these municipalities.
West Nile Virus is transmitted through the bite of an infected mosquito—primarily species in the Culex genus—which contract the virus after feeding on infected birds. While most individuals infected show mild or no symptoms, WNV can occasionally cause severe illness, including West Nile encephalitis.
County trucks (marked with county emblems and ID BU2145) will apply Biomist 3+15 at a rate of 0.75 ounces per acre.
Biomist is an EPA-registered adulticide with a very low toxicity profile for mammals. Applied in a ultra-fine mist (around 25 microns) at dusk, it targets flying nocturnal mosquitoes while minimizing impact on non-target daytime pollinators like bees and butterflies. The active ingredients break down rapidly in sunlight.
While the product poses minimal risk, officials advise residents in the active spray zones to stay indoors, close windows, and turn off window air conditioners or intake vents during application. Operators will shut off spray nozzles when within 50 feet of bystanders.
County health officials urge property owners to take proactive steps to reduce mosquito breeding grounds:
Eliminate Standing Water: Empty birdbaths, clogged gutters, flowerpot saucers, discarded tires, and outdoor toys at least once a week.
Treat Un-drainable Water: Use Bti (Bacillus thuringiensis israelensis) products—such as mosquito dunks or bits—in stagnant pools or rain barrels. Bti is a naturally occurring soil bacterium that kills larvae without harming pets or wildlife.
Personal Protection: Wear long sleeves, pants, and EPA-registered insect repellent when outdoors around dusk and dawn.
