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This Texas fly can bite, leaving irritated skin. It loves the heat and moving water

Black flies, also called buffalo gnats or turkey gnats, are known to bite people during the day — particularly around the neck and head, leaving skin itchy and swollen. Black fly season lasts from April to July.

Black flies are small flies up to 5 mm that are active during the day, fast and strong fliers. They have a characteristic “hump-back” and can be black, gray, light tan or yellow in color. Black fly species can commonly be found along fast-moving rivers, particularly in northeast Texas.

Female black flies have mouth parts to bite and feed on blood of people, domestic animals, poultry and wildlife. The painful bite can cause localized swelling, and in extreme cases anaphylactic shock.

The larvae can be found just beneath the surface of rapidly flowing fresh water, according to Texas A&M. Most species develop while attached to submerged rocks or logs in shallow moving waters of streams and rivers, while some do well in sandy-bottomed streams and slow, muddy water. Development can take anywhere from two weeks to more than two months.

Adult black flies spread a long ways from their breeding habitats to feed, having been found far from streams and rivers in urbanized areas of Texas. Outbreaks are likely to occur whenever conditions for them to successfully breed in high numbers are present, most notably warmer temperatures and high amounts of rainfall that contribute to aquatic habitats needed for their development.

During periods of adult activity, the biting flies can become a nuisance. If not staying indoors, experts at Texas A&M say those working outdoors should dress in long pants and a long-sleeved shirt, wearing a cap and a mesh veil to protect themselves. While insect repellents can be used, particularly to the neck and head, they may not be very effective against the strong, fast flies.

Read Dalia Faheid's short list of best repellents here.


September 27, 2023

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Dalia Faheid

Fort Worth Star Telegram

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A 20% DEET Premium Controlled-Release Lotion will work well against mosquitoes, but Dr. Zimring says he prefers the 20% Picaridin lotion since it also protects against ticks, gnats, chiggers, and flies. (In both instances, he recommends Sawyer brand.)

Rachel Schultz
Editorial Director


Part of spending time outside means battling ticks, mosquitoes, and other biting insects. For this, Nelson swears by permethrin.



And out of the products we tested, Dr. Zeichner highly recommends Sawyer Products 20% Picaridin Insect Repellent.

Samson McDougall