Sampling and Spray Operations

The Pennsylvania Black Fly Suppression is based on field monitoring and laboratory identifications of black fly populations throughout the Commonwealth. The information gathered as a result of these processes is used by DEP biologists to schedule treatment operations, in coordination with aerial application contractors. DEP biologists are also responsible for reviewing treatment effectiveness.

• Prespray samples help determine the need for and timing
  of treatments
• 15-minute sample taken from riffle/run black fly habitat areas
• Sample vegetation, debris and rocks, with fingers and forceps
• Transfer larvae/pupae to vials of 70% ethanol for Lab Identification
• Postspray Samples help determine treatment effectiveness

• Sampling sites established at parks, schools, ballfields, & other outdoor recreation areas.
• Disturb vegetation for 100 meters, lay down trail of CO 2 and human scent
• Take 9 sweeps (3 sets of 3 sweeps) with 10 in. net, shake down adults
• Transfer adults to labeled sample bottle of 70% ethanol for Lab Identification
• Collectors are prohibited from smoking or using tobacco products, and may not apply insect repellents during the collection process

• Samples delivered to PA DEP Laboratory for identification
• DEP biologists and interns identify samples using microscopes and taxonomic keys
• Species identifications and counts, as well as life stages, are recorded in GIS-based data system
• This information is used in planning and reviewing statewide black fly treatments

• Treatments are scheduled only when larval sample results indicate presence of human pest species (i.e. Simulium jenningsi). Sprays are conducted at preselected locations in treated waterways upstream of fast flowing areas where larval habitat is present.  
• DEP biologists direct treatments in coordination with aerial application contractors. Aerial sprays with helicopters can be seen spraying waterways and ground crews can be seen using backpack sprayers or pouring jugs to apply material from bridges or wading in streams during spray operations. Anyone concerned at the sight of helicopter or ground personnel is encouraged to call their county emergency management office to verify that a black fly treatment is taking place in their area on that day.
• Treatments consist of aerial applications of environmentally-safe, naturally-occurring soil bacteria, Bti. The Bti material is a liquid that is brown in color and is not an aerosol. The material is sprayed in bands at a spray site perpendicular to the flow of the treated waterway where it quickly disperses into the water.    
• Reviews of treatment-effectiveness after each treatment are conducted by DEP biologists.
• There is no approved or effective product to spray adult black flies due to the behavior of the insect and large flight distances traveled after hatching. Therefore, no adult black fly sprays are conducted on land and the program only conducts treatments in waterways to suppress black fly larval densities before they hatch. 
• DEP notifies federal, state, and county authorities, including emergency management personnel, of upcoming black fly treatments. The Department maintains a list of all black fly sprays at the DEP Vector Management website.

• Bio-monitoring of aquatic macroinvertebrates and fish is conducted by DEP on selected treatment streams to ensure there are no environmental impacts
• Samples collected using US-EPA Rapid Bio-Assessment Protocols at Bti-treatment sites and compared to samples from untreated control sites.
• Data analyzed using metrics for species richness, diversity, abundance, population density, composition and tolerance
• Results confirm that a carefully managed Bti treatment program can provide effective black fly control with no major impacts to non-target organisms
• A DEP-funded five-year study by the Academy of Natural Sciences of Philadelphia and Stroud Water Research Center found no significant impacts to fish and insects