The Pennsylvania Department of Environmental Protection (DEP) is scheduled to conduct aerial black fly suppression operations along the Delaware River in Bucks and Northampton counties as well as the Lehigh River in Lehigh County on Wednesday.
The spray targets larvae growing in waterways before hatching as black flies (biting gnats), leaving their aquatic habitat to affect both animals and people. The black fly suppression program reduces the population, providing relief for outdoor recreation in spring and summer months, according to officials.
The spraying on the Delaware River will take place later in the day between the Delaware Water Gap (Northampton/Monroe county line) and the Trenton, NJ city limits. Potential landing areas in Bucks County include the T3 Ranch in Durham Township, the Erwinna/Delaware Valley Fire Co. in Tinicum Township, and Thorpe Farm in Upper Makefield Township.
Aerial operations, according to officials, will involve the application of Vectobac 12SC (a brown, viscous, liquid material that smells like fish oil and has a chocolate milk appearance) from a helicopter. The helicopter will apply the Vectobac perpendicular to the river flow in designated areas by flying back and forth across the river and discharging the material from a boom arm. The material is then carried downriver. The active ingredient in Vectobac is Bacillus thuringiensis israelensis (B.t.i.), is a naturally occurring soil bacterium. The helicopter will apply the B.t.i. to designated areas every few miles along the treated waterways. Application is done by first circling the area to look for people on the ground/in the water or for obstructions in the air.