[DSM note: This is not what we want to happen. The sprayers cite no evidence that spraying pesticides in the air impacts the incidence of West Nile Virus (of which there has been one known human case in PA so far this year). This large residential and business area in the center of Downingtown contains many dwellings and bodies of water. Anyone in that area, please try to observe and let us know:

DSM wants to help protect people and the environment but we can’t do it without volunteers on the ground to observe and let public officials know what you think.]

Press release, Chester County Health Dept., 7/22/17

West Chester, PA – The Chester County Health Department will conduct a mosquito control treatment spray in portions of Downingtown Borough and East Caln Township (map of treatment area).

The treatment is scheduled for Thursday, August 24th from 7:45 pm to 11:00 pm. The rain date for this event is Monday, August 28th from 7:45 pm to 11:00 pm.

The Chester County Health Department conducts mosquito control treatment in areas with high levels of mosquito activity and where multiple mosquito samples have tested positive for West Nile Virus (WNV). After exhausting all other available mosquito control strategies, spraying is conducted to reduce residents’ risk of WNV infection. Anyone living in an area where mosquitoes are infected with WNV is at risk, but the risk of infection is highest for people who work outside or participate in outdoor activities. Less than 1% of people infected will develop serious illness. While serious illness can occur in people of any age, people over 60 years of age, people who have received organ transplants, and people with certain medical conditions such as cancer, diabetes, hypertension, and kidney disease are at the greatest risk for serious illness.

The Chester County Health Department uses a truck-mounted sprayer to apply 1.5 ounces of U.S. Environmental Protection Agency-approved product (DeltaGard) per acre of land. The mosquito control spray becomes inactive in just a few hours or with sunshine. Sprays are conducted after sunset, when mosquitoes are most active and bees have returned to their hives. Sprayers are turned off near bodies of water and apiaries to protect aquatic life and bees. The Chester County Health Department also notifies registered beekeepers and residents who are listed as hypersensitive in a designated spray area prior to conducting a spray. People who are concerned about exposure to mosquito control products can reduce their potential for exposure by staying indoors with children and pets when their neighborhood is being sprayed. If you would like to take extra precautions after the spray is completed, you can rinse off outdoor furniture or playground equipment before use.

Although spraying helps to reduce mosquito populations, the Chester County Health Department encourages residents to “Make You and Your Home a Bite-Free Zone” to prevent WNV and other mosquito-borne diseases. Because mosquito-borne diseases are spread through the bite of an infected mosquito, residents can reduce their risk by using insect repellent and other personal protection and getting rid of standing water on their property…

read more for general advice at Chester County Health Department