We have a big fly problem inside and outside our home. We live in a log home and have sealed all obvious cracks and other openings both inside and outside the home with urethane foam , but flies are still entering the home in large quantities and swarming onto two very large windows forming most of the south-west wall of my home. We built have lived in the home for 14 years, and even though we have had some problem in the fall in the past, this year we cannot begin to control the problem. I am vacuuming the windows of live flies three-four times a day, removing as many as 80-100 flies each time. There are flies swarming on the outside of the windows, also, but I don’t think it is as bad there. The area we live in is rural and essentially arid semi-desert with lots of pinion and juniper trees. There is some ranching within half of a mile, but no big cattle operations, only 4-5 animals. We have only one small dog and he is an inside pet and housebroken. The house has two attics. One on each side of the house with a vaulted area in between. The vaulted top has no voids as it is completely foam filled, sandwiched between the roof and a layer of particle board, and covered with aspen plank ceiling. The attics are each truss built and heavily insulated from the living areas below, however, there is a log wall between the attics and the vaulted section on both sides that are somewhat suspect because the chinking and sealing we did is only on the living quarter side of those walls.
I apologize for the complicated story, but I thought you might see where we could apply a specific chemical that might treat the house and would last for a long time—not to kill the flies, but to keep them out all together.
If you are interested in helping us, please feel free to offer your input, and we will give it strong considerations.
It sounds like you might have cluster flies based on the description you provided. You can read up on them in our FLY CONTROL ARTICLE. Details on them can be seen just below Common House and Blow Fly text. As you’ll learn, they typically invade homes during the fall season and once your home is targeted, they’ll return year after year. To keep them out, you should apply the DRIONE DUST to any attic spaces as well as other cracks and crevices. Ideally this should have been done before you sealed the home but even now it will help. Spraying the outside with CYPERMETHRIN will also repel them. And in the future, be sure to add some INSECT REPELLENT STAIN ADDITIVE to any products you use on the logs.
Lastly, every window should be set up with a FLY POWDER TRAP. These do a great job of collecting and killing any that may end up inside and are easy to deploy.
Here are direct links to the information and products listed above:
Cluster Fly Article: http://www.bugspray.com/catalog/products/page306.html#cluster_flies
Insect Repellent Paint/Stain Additive: http://www.non-toxic-pest-control.com/repellents/nbs-repellent-insect-spray
Fly Powder Trap: http://www.bugspray.com/catalog/products/page1343.html