This helicopter was flying over the Conewango Creek in North Warren on Thursday morning as part of ongoing black fly suppression initiatives.

Black fly spraying continued in Warren County this week.

“An aerial black fly suppression operation has been scheduled for Wednesday and Thursday, September 15 and 16, 2021, on the Allegheny and Clarion Rivers, and Conewango, Brokenstraw, Tionesta, Oil and French Creeks,” Tom Decker, community relations coordinator with the DEP, told the Times Observer.

“This operation will begin Wednesday when spray operations in Southwestern PA have been completed,” he added. “Flights will be conducted in Warren, Clarion, Forest, Venango, Armstrong, and Elk Counties.”

According to DEP, the helicopter conducting the treatment is a Bell OH-58 with the Ttail numbers N653HA and is painted grey with blue and red stripes. Helicopter Applicators Inc. conducted the spraying.

The Times Observer previously reported that the substance being dispersed — Vectobac 12AS, a Bti product manufactured by Valent Biosciences, will be dispersed and is a bacterial larvicide — not a chemical. It’s the only product used in Pennsylvania’s waterways for black fly suppression.

DEP said the substance resembles the consistency of chocolate milk.

“The helicopter will fly low near tree top level and release the Vectobac 12AS at various predetermined positions on each stream,” Decker said.

According to the Department of Environmental Protection, a total of 35 counties are included in the state’s black fly control program.