The state Department of Environmental Protection began its annual black fly control aerial spray program on Monday, starting with nearly 120 stream and river miles in four eastern counties.
Through August, 45 rivers and streams spanning more than 1,500 miles in 32 counties will be monitored and treated as needed. Spraying activities will be performed by helicopter and the frequency will depend on black fly surveillance results and weather conditions. Treatments cannot occur during periods of heavy rain or when water levels are high. Fast-moving water can carry away the spray product too quickly, making the treatment ineffective.
DEP uses Bti, a naturally occurring bacterium, to target 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, fish, birds or other insects.
Spraying greatly reduces the black fly population, making it easier for Pennsylvanians to enjoy outdoor activities during the warmer months of the year, according to the Department.
State authorities will notify county and local emergency management officials prior to any spraying activity to make them aware that helicopters seen flying over creeks, streams and rivers are working on behalf of the state's black fly program. Anyone with concerns about the sight of a helicopter is encouraged to call their county emergency management office to verify that a black fly treatment is taking place in their specific area on that day.
In Lycoming County, spraying will take place on Loyalsock Creek, Pine Creek, the West Branch of the Susquehanna River.
In Union County, spraying will take place on Penns Creek and the West Branch of the Susquehanna.