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MMCD's black fly program uses Integrated Pest Management
Black flies, or "biting gnats," are a type of fly that are found near rivers and streams throughout Minnesota. Their larvae develop in running water and the female adults feed on the blood of mammals, including humans, to produce their eggs. They can be quite aggressive and may swarm in large numbers.
MMCD has had a black fly program since 1984 when small streams began to be monitored and treated. In 1996 the full-scale large river treatment went into effect.
Like the Mosquito Control program, MMCD's black fly program utilizes Integrated Pest Management which consists of three components: surveillance, identification, and conrol
Surveillance
The first step is to determine where black fly larvae are developing by doing surveillance on rivers and streams. River surveillance is done using tapes or "substrates" that are placed in the water and checked after about one week. Samples are sent to the MMCD entomology lab by field staff to determine what specimens are present.
Field staff also conduct adult surveillance for black flies by using CO2 traps and sweep net collections near high activity areas.
Identification
Once the samples are collected, the MMCD entomologist who specializes in black flies takes a look at the samples under a microscope and identifies them by species. They are seeking to determine if there is enough black fly larvae to be over a set threshold and if they are one of the species that MMCD has permission to control. The Minnesota Department of Natural Resources is the decision-maker for what control work is done on large rivers in the District.
Control
If the collections are over threshold and the species is approved, field staff will return to the areas with control materials to conduct a treatment. Treatments are done using liquid Bti, which is specially formulated to only target black flies when applied in a river. For smaller streams treatments are done on the ground and for larger rivers treatments are either done via boat or bridge.
Field staff will conduct a "checkback" where they revisit the tapes to determine if the black fly larvae was impacted and non-target aquatic species were not.
Check out the video above to learn more about what MMCD does for the black fly program!
Credits
PRODUCED BY: Martin Hendrickson, MMCD Public Affairs Assistant
FEATURING: Shawn Partyka, MMCD Field Operations Supervisor Maple Grove, Loren Lemke, MMCD Field Operations Supervisor Maple Grove, Carey Lamere, MMCD Black Fly Entomologist/Technical Services, Dan Stith, MMCD Field Operations Supervisor Andover, and Andrea Lectka, MMCD Field Operations Supervisor Maple Grove.
