Black Fly Suppression Program

The Black fly spraying program is a joint effort of Venango County and Pennsylvania DEP.  Field personnel of the DEP monitor the black fly populations along the major waterways in the county.  These include French Creek, Sandy Creek, Oil Creek, Sugar Creek and of course the Allegheny River.  When the populations reach a predetermined level, (nuisance level) the DEP orders spraying of the affected stream.  

Pennsylvania has contracts with aerial applicators that will then spray the designated waterways.  The contractors use a product called Bacillus Thuringiensis Israeliensis (BTI).  It is a naturally occurring bacteria found in aquatic soils around the world.  It is a safe and effective alternative to the use of chemical insecticides.  Spray notification is unavoidably short.  With the variables of weather and stream conditions to contend with, a two day notice of spraying is all that can be managed.

Click here for more information about DEP's Black Fly Suppression program.

Participating Pennsylvania counties in DEP's Blackfly Suppression program. Source: PA Department of Environmental Protection

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The life cycle includes four stages: egg, larva, pupa, and adult (Figure 1). All are aquatic except the adults, which leave the water to search for food and mates. Source: PA Department of Environmental Protection

Program Funding

• State/county cost-sharing of treatment operations, as set forth in county agreement.
• All administrative and monitoring costs are paid entirely by DEP, at no cost to the county.
• Commonwealth funding for the program is achieved through an annual state budget appropriation.
• Counties are invoiced for the local share of the project at the end of each treatment season.

Additional Resources

• Submit a black fly complaint
• Treated streams in Pennsylvania
• North American Black Fly Association
• How to Protect Yourself Against Black Flies
• Sampling and Spray Operations
• Frequently Asked Questions