PA DEP will be conducting an aerial black fly suppression operation

An aerial black fly (gnat) suppression operation is scheduled for Thursday August 7, 2025, on the Neshaminy Creek, Delaware and Lehigh Rivers. The operation will begin at approximately 8:00 am at Doylestown Airport in Bucks County and will include flights in Bucks, Lehigh & Northampton Counties. The helicopter used for this operation will be a Bell Jet Ranger OH-58+ with tail number N653HA and is painted white with blue and red stripes.

Spray operations will specifically take place within the following sections of each river:

  * Neshaminy Creek: Between Playwicki Park, Langhorne & the Rt 611 Bridge in Doylestown.        

  * Lehigh River Between Easton & Sladington

  * Delaware River Between Slateford PA & Trenton NJ.

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.

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. Any questions about this operation may be directed to me and more information regarding the PA Black Fly Suppression Program can be found on our website at Black Fly (pa.gov)

Additional information:
Vectobac 12AS label
Vectobac 12AS SDS Sheet

For more information on the program please visit the Black Fly Program website: Black Fly.