Union County schedules helicopter black fly control over creeks

Low-flying helicopters over Penns and Middle creeks were part of Union County’s black fly control push, with a Bell OH58 A+ Jet Ranger, tail number N655HA, scheduled to release larvicide at predetermined points on the streams. The operation was set for Tuesday, May 12, 2026, in Union and Snyder counties, putting the work squarely in the creek corridors most likely to be noticed by anglers, paddlers, farmers and anyone spending time near the water.

The county said Helicopter Applicators Inc. was dispersing Vectobac 12AS, a Bti product made by Valent Biosciences. Bti stands for Bacillus thuringiensis israelensis, the bacterial larvicide Pennsylvania uses in waterways for black fly suppression. That matters because the helicopter work is not a broad chemical spray over neighborhoods or town centers. It is a targeted treatment aimed at larvae in the water, with the aircraft flying near tree-top level as it moves along the streams.

The Pennsylvania Department of Environmental Protection says the statewide Black Fly Suppression Program was in its 41st year in 2026 and covered 48 rivers and streams across more than 1,800 miles of waterways. DEP says the goal is to reduce black fly populations to tolerable levels during the spring and summer recreational season. The agency also says Bti breaks down quickly in the environment and is not harmful to fish, birds, people or other insects. Treatments focus on the larval stage and are not conducted on land.

The program remains a cost-shared effort. DEP says the state pays most of the cost, while counties pay part of the application expenses. It now operates in 35 counties and serves more than 6.6 million residents. Those are the kinds of details Union County residents are likely to watch closely as the helicopter work continues around Penns and Middle creeks, where black flies can make warm-weather outdoor use far less pleasant.

The bigger accountability questions are straightforward: how do officials decide when a spray is necessary, what does each treatment cost, how is effectiveness measured once the helicopter leaves, and what environmental or health concerns do local residents want answered before the next flight? DEP’s program history says black flies have been a recognized pest in Pennsylvania since the 1970s, and the statewide effort traces back to Neighbors Against Gnats, the grassroots group that pressed for larvicide sprays on the Susquehanna River. That long history is part of why the creeks were on the schedule again.