We bought our cabin August of 2011 and this is the first summer we have discovered biting flies! The back of my legs are covered with little red, itchy, bumps and they are not from mosquitoes! So, I have been doing a little research on these annoying pests!
My first thought was that these flies look very similar to a housefly, only smaller; however, research shows that the common houseflies do not bite. Looking through pictures of biting flies, I found that these biting flies are not what some people are calling Black Flies, but are actually called Stable Flies. So, I am not surprised we find so many near our corral.
In Colorado, Stable Flies usually feed on livestock; however, I have definitely witnessed them on our neighborhood dogs and humans. These flies are blood feeders; their bites are painful and produce swelling and itching as the result of injecting their saliva. Stable Flies feed during sunny, warm days and are most active during mid-morning and right before dusk. Biting seems to be worse right before a rain storm. Scientists say the biting will end when the night time temperatures begin to drop and kill the adult flies and larvae, which will be about the middle of October.
The life cycle of a Stable Fly is about 3-4 weeks from egg to a mature adult. Adults live about 2 weeks. Females may lay several hundred eggs, there may be 2 to 4 generations per year, both adding up to a fast growing population.
The breeding habitat for Stable Flies is moist straw, hay, or grasses mixed with old horse (not cow!) manure. When the mixture dries out, the larvae die. Organic, decaying, moist, materials on our properties are also breeding habitats. So, I am not surprised that we have more Stable Flies than normal this summer because of all the rain we have received.
I have used Mosquito repellents to try and prevent Stable Flies from biting, but have found NONE that work! Mike Felix told me about tiny parasitic wasps that will lay their eggs in the manure mixture and their larvae will then feed on and kill the Stable Fly larvae. Even though these wasps are normally found in our environment, there are not enough of them to control the Stable Flies. Wasp eggs hatch quicker than the Stable Fly eggs; however, a female fly can lay 3 times as many eggs as a female wasp. These wasps can actually be purchased on the internet and can help reduce fly larvae by about 90% if breeding sites are cleaned up regularly and wasps are released about every 30 days throughout the summer. Wasps do not sting or bite humans or animals.
For more information about Stable Flies go to the following websites:
If you know of other Stable Fly bite prevention methods, please share it with us by making a comment below. Also mentioned in the documents I read during my research was a botanical solution such as marigold extract or an environment friendly fly trap. Some neighbors have also mentioned drier sheets. I have successfully used them by my pillow at night for mosquitoes! So, the next time you see me walking near the pond; do not laugh at me for the drier sheets stuffed in my socks!