Monday, June 1, 2009

Black Flies

Weigela Bush "Red Prince"

I think I've identified the miserable biting bug that is plaguing gardeners. It is the Black Fly Simuliidae. Also known as the buffalo gnat, turkey gnat or white socks.

Like mosquitoes, a relative, the female black flies gain nourishment by feeding on the blood of other animals. The male eats mainly nectar.

Water plays a huge role in the breeding process which may explain why we have so many this year. The water must be moving for the immature stages to develop. Since many of our ditches, streams and lakes are normally still water, the population has expanded with the amount of rain run-off this spring.

When conditions are good, the Black Fly occur in enormous numbers - no kidding!! Each female lays from 200-800 eggs. The flies live from two to three weeks (up to 85 days). There will be large populations starting in April as long as the high water causes water to flow (sometimes into July).

They do not like polluted water and the increase in non polluted water across Illinois has increased their numbers. Should we blame Al Gore for this problem?

Adult females feed on the blood of humans, cattle, horses, sheep, goats, poultry, other livestock and wild mammals and birds. Each black fly species may prefer one type of host over another. They have hurt the tourism economy at recreational sites, but even worse, have been known to cause weight loss and kill domesticated agricultural livestock especially poultry.

Black flies are daytime biters, preferring low wind conditions. They are not restricted to shaded or humid sites and usually do not go indoors (unless carried in on your hair).

They are attracted to hosts from a distance by smell, heat, and by sight. The female flies will swarm around and crawl on the host preferring the head, hair, and ears as well as any skin that is exposed.

The bites can itch and persist for several days. The fly bites by cutting into the skin and feeding on the pool of blood that forms in the hole they make. Anticoagulants injected into the feeding site can cause mild to severe allergic reactions in sensitive individuals.

Some people are very attractive to black flies and others appear to repel them.

Control of black flies is difficult because of the number of potential breeding sites. Some states have funded control programs (although Illinois doesn't list any). In Africa, the black fly has been known to spread river blindness and other serious diseases in the Central and South America.

Long sleeve shirts, long pants, fine screen netting over the head help prevent feeding. Repellents containing "DEET" formulations are not very effective and may even attract more flies. It is said more protection may be given by herbal-based treatments with an active ingredient of geraniol. Permethrin products designed specifically to repel ticks also work as a treatment when applied to clothes not skin.

The bottom line recommendation is avoid exposure - which would mean staying indoors. Not a good option for farmers, the construction trades, gardeners, and children. Another herbal suggestion is to eat a diet high in thiamine (Vitamin B) as it gives off a repulsive odor that only insects can smell. Thiamine is found in whole-grain cereals, bread, red meat, egg yolks, green leafy vegetables, legumes, sweet corn, brown rice, berries, and yeast. Do NOT hold me responsible (good or bad) for the repercussions of a high Thiamine diet!! I'd post a picture but most are copyrighted and the only ones I've actually examined have been squished when I hit them. They look like a tiny black fly with a hump behind the head.

If you have severe allergic reactions to bites, seek immediate medical treatment. Even if not highly allergic, it is important that you do not scratch the site and cause infection.

For those of us who have normal and pesky reactions - treatments are similar to other bug bites: wash the site with soap and water. One of the following may work for you: apply an ice cube wrapped in cloth, a soda/water paste, a paste of salt and water, or a paste of meat tenderizer and water. You may treat itching at the site of the bite with an over the counter antihistamine such as diphenhydramine (Benadryl) in cream or pill form. Calamine lotion also may help relieve the itching.

I will attest that putting on a treatment for existing bites only attracts more flies if you go outside again with that treatment on your skin. Apparently it is a sign seen only be insects that says: Good food, unlimited quantities, proven triple A rating, dining at your convenience, immediate seating, no waiting, credit cards accepted and Come one - Come all!


  1. In Northern Ontario , we use Avon's Skin-So-Soft , much to the Avon's chagrin initally- but now a selling feature . A little spray bottle of the oil mixed with water in your pocket is essential during blackfly season . Every fisherman keeps it in the kit . The best way is still to use it in a warm bath in the morning ...heat and moisture allow it to permeate your skin and lasts most of the day. The most important thing is that it works . It is nonharmful to the environment .

  2. Thanks "thepowmill" for the good advice. I used this years ago and hadn't though of it in ages. It will be my this years effort!

    Have a great weekend - maybe we'll see spring soon. Diane