How many species of black flies found in Minnesota are considered pests?

• A. 2
• B. 4
• C. 6
• D. 8

Answer: (B)

The question tests how many black fly species in Minnesota are actually considered pests, which depends on the biting behavior and nuisance level of the species. Only a subset of black fly species produce the large, biting swarms that irritate people and livestock, so those are the ones labeled pests. In Minnesota, four species are recognized as pests. This matters for targeted monitoring and control, focusing efforts during the peak emergence period rather than treating all black flies the same. Other counts would misrepresent the situation: too few would miss some problematic species, while too many would overstate the scope of pest species.