DEP announces 2022 Black Fly Season with City Island demonstration

Harrisburg, PA – The Pennsylvania Department of Environmental Protection (DEP) announced its 2022 Black Fly Suppression Program today at Harrisburg’s City Island and provided a demonstration of the various tools, including a boat, used to decrease black fly populations across the commonwealth.

The program involves aerial and backpack spraying on roughly 1,700 stream miles in 36 counties in the commonwealth.

The season runs April 1 through September 2022.

“Black flies are a pest and get in the way of enjoying outdoor recreation,” said DEP Secretary Patrick Mcdonnell. “Thanks to increased funding for the program, we are able to treat more miles of streams and rivers more often to be able to make sure that Pennsylvanians and visitors can fully enjoy our natural resources.”

This year, 48 rivers and streams spanning more than 1,700 miles will be monitored and treated as needed. Spraying activities will be performed both by helicopter and ground crews. The frequency will depend on weather and biological conditions. Treatments cannot occur during periods of heavy rain or when water levels are high as these conditions lower the effectiveness of the treatment and significantly increase the cost of the control operations.

Doug Orr, environmental group manager for DEP’S vector management program, which oversees the Black Fly Suppression Program, displayed samples of black fly larvae and Bti, the organic material used to suppress black fly populations.

Bti, a naturally occurring bacterium, targets the larval stage of four specific human pest black fly species. This bacterium degrades quickly in the environment and does not harm the aquatic ecosystem, birds, other insects.

Prior to any spraying activity, DEP notifies county and local emergency management officials. Helicopters can be seen flying over waterways and ground crews using backpack sprayers off bridges and wading in streams conducting control operations on behalf of DEP’S Black Fly Suppression Program. Anyone concerned at the sight of a helicopter or ground personnel is encouraged to call their or county emergency management office to verify that a black fly treatment is taking place in their area on that day.

Anyone near a spray site when it is treated may notice a strong, fishy odor. The manufacturing process of the product uses fish meal. In a case where winds carry small droplets of Bti onto humans, pets, or boats, wash the material off with fresh water and contact DEP to report the incident.