David Zierden, the Florida State Climatologist, sent along this note on yellow flies in the Southeast:
Folks who frequent or work outside close to wooded areas in Florida and the Southeast in the summer are familiar with yellow flies. What we call “yellow flies” often refers to several different species including deer flies, true yellow flies, and horse flies. These blood-sucking biting flies breed and lay their eggs in damp wooded areas and wetlands. The larvae live in wet soils over the winter before emerging from their pupae in the summer months.
Florida and the Southeast experienced the wettest summer on record last year and since then winter and spring rainfall has been plentiful. With all of the rain, there has been a wide expanse of suitable habitat for the biting flies to breed and mature. While I do not have any hard data to back this up, almost everyone I have talked to agrees that this is the worst summer in memory for biting yellow flies.
If you are working or recreating outside near wooded areas, be sure to bring plenty of bug repellant (with DEET for maximum effectiveness) and wear long clothing. It looks like the plague of biting flies this summer is an unanticipated result of last year’s climate extremes.
Everything you ever wanted to know about yellow flies…