everal areas in Illinois have reported large numbers of black flies that have been biting poultry, pets, livestock, and people.
Several poultry have died as a result of these attacks and people have sought medical attention.
Here are answers to frequently asked questions about buffalo gnats or black flies.
What are they?
Buffalo gnats or black flies are blood-sucking flies of the Simuliidae family. The females may attack people and animals in an effort to have a blood meal for egg production.
Do they pose a public health risk?
In humans their bites typically cause pain, itching, and swelling. However, those who have an allergic reaction may have more serious complications.
Will they harm my animals?
The consequences for animals can be more severe. Livestock and poultry are sometimes killed by the flies when bitten by large numbers of them. Death can be due to anaphylactic shock, toxemia, blood loss, or suffocation when the flies are inhaled. Some species of black flies can transmit a blood-borne parasite that affects poultry called, leukocytozoon.
When can I expect them to be a problem?
The adults emerge in the late spring to early summer and are known to travel more than 10 miles in search of a meal. The larvae are very sensitive to water temperature. Once the water temperature reaches 66 -75 degrees F the larvae will die and the buffalo gnat season is over until next year.
Why are they causing problems now?
The eggs are laid in running water and the larvae are filter feeders. They are sensitive to sediment, toxins, and low oxygen levels in the water. With adequate rainfall and as surface water quality improves the conditions are more favorable for the flies.
How can I protect myself from them?
Black flies are outdoor, daytime feeders so the best protection is avoidance. If you must be outside, light colors and long sleeves are recommended. Permethrin treated clothing and insect repellants containing DEET have been used with limited success.
How can I protect my animals from them?
Animals that are housed indoors are at a much lower risk of being bitten even if the building is not fly-proof. It is recommended that poultry be kept indoors in a darkened barn during the day. Usually fans or some means of cooling are needed. Permethrin-based fly control products are recommended for livestock and poultry.