If you have been outdoors this spring, especially in eastern Iowa, I am sure you have experienced the joy of many tiny flies surrounding your head. These are black flies, also known as Buffalo and Turkey gnats. There are several species of black flies, and some species are more prone to bite humans than others. The bite of the black fly is painful, and they inject venom when they bite. The venom causes local swelling and itching at the site of the bite in many people, and some people can even suffer severe allergic reactions. In the U.S., black flies do not transmit any diseases to humans.
Black fly larvae occur in fast moving streams and feed on algae and other organic matter. Black flies are one of the many insects that are not a problem every year, but when they have a high population they are very noticeable and irritating. Control of black fly breeding areas is not feasible, and unfortunately mosquito repellants, such as DEET, do not seem to deter them much. Protective clothing may be a more feasible method to avoid bites. On a more positive note, black fly adults only live for about 3 weeks, and there is only one generation in a year, so they should only be biting us for another few weeks.
This article originally appeared in the 5/28/2004 issue.