NOTICE

[Northampton County, PA] – An aerial black fly (gnat) suppression operation is scheduled for Wednesday, July 9, 2025. The operation will begin after 8:00 A.M. at Washington’s Crossing and include flights over designated sections of the Delaware River, Lehigh River, and Tohickon Creek.

The helicopter used for these operations will be a Bell OH58+ (tail number N659HA), which is grey with blue and red stripes. Helicopter Applicators Inc. will carry out the treatments.

Spray operations will specifically take place within the following sections:

• Delaware River: Between Slateford in Northampton County and the area near Trenton, NJ/Yardley, PA in Bucks County
• Lehigh River: Between the confluence with the Delaware River and Allentown
• Tohickon Creek: Between Point Pleasant and PA 611

Helicopter Applicators Inc. will be dispersing Vectobac 12AS, which is a Bti product manufactured by Valent Biosciences. Bti is short for Bacillus thuringiensis var. israilensis, which is a bacterial larvicide, not a chemical, and is the only product used in Pennsylvania’s waterways for black fly suppression. Vectobac 12AS is a brown liquid with a fish oil odor. The helicopter will fly low near tree top level and will release the Vectobac at various predetermined positions on each stream. Vectobac is not toxic to fish or other aquatic organisms.

Please note that this work does NOT involve a helicopter spraying over the entire county, and applications will only occur on the specific waterways listed in this notice.

Black flies, also known as biting gnats, are considered a pest that can inundate people seeking outdoor recreation in the warmer months, especially around rivers and streams.

For more information on the program, please visit the Black Fly Program website: Black Fly (pa.gov).

Information provided to TVL by:
Northampton County Executive Office
669 Washington Street
Easton, PA 18042