WHO: Pennsylvania Department of Environmental Protection

WHAT: Aerial Spraying for Black Flies

WHERE: Delaware River

WHEN: Friday, May 29,2026

[Northampton County, PA] – An aerial black fly (gnat) suppression operation is scheduled for Friday, May 29 on the Delaware River. This operation will begin at Washington Crossing in Bucks County at 8:00 a.m. and will finish in Northampton County. This aerial application will include flights in Bucks and Northampton Counties. The helicopter will be a Bell OH58 Jet Ranger with the tail number N655HA and is painted grey with blue & red stripes.

Please note that this work does NOT involve a helicopter spraying over the entire county and applications will only occur on the specific waterways: Delaware River: Between Trenton, New Jersey and Slateford, Pennsylvania.

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. Attached is a copy of the Vectobac label and safety data sheet in case you would need information on the product.

For more information on the program, please visit the Black Fly Program website: Black Fly (pa.gov). If you have any questions regarding these operations, please contact 215-327-1524 or email the Vector Management Program at pmages@pa.gov.

Information provided to TVL by:
Northampton County Executive Office