Great info on your website! We live in Colorado and the gnats are getting worse every year. We can’t do anything outside w/o them flying in eyes, nose, ears and mouth. They don’t seem to bite, just drive us insane landing on us or IN us!
We have 35 acres, but really just 3-5 or so where we spend time since the rest is rocky and steep. The gnats drive the horses nuts too. So I’d like to be able to spray as big an area as possible. We don’t really have pasture since it is generally dry here, but the horses do nibble on some sparse grass and weeds and I need to make sure that if we sprayed around them that it wouldn’t hurt them. Probably I’d focus spraying on the trees (evergreens) in the pastures and the heavily weeded areas outside the pastures since that seems to be where the gnats live. We’re also slowly trying to destroy the weeds, but we just got the property and it was empty for a year and weeds took over.
Horse fly spray contains permetherin, so I know it doesn’t hurt them sprayed on them, but I don’t know about if they eat something that’s been sprayed.
Thanks for any advice!
In our GNAT CONTROL ARTICLE, we list several products with different ways to apply each one. This list can make matters confusing with all the options to choose from but many of these won't work for your situation. You see, once you get to farm sized properties with several acres of land to treat, you really get limited in what's practical to use. Based on the size of your farm, I don't think you have many choices here. I recommend going with either the SOLO BACK PACK FOGGER or the GOLDEN EAGLE THERMAL FOGGER. Both will handle the treatment well and should provide years of reliable service.
The chemical used should be the PERMETHRIN 10. As our article explains, this active can be directly applied to your horses and in fact is a great way to provide relief to them if they're under attack. But it can also be used on structures and in the turf. Since your horses may actually graze on some of the treated plants, change over to the VEGETABLES PLUS PERMETHRIN for any of the plants they might eat. It has a "7 days to harvest" label for people and if you follow this guidelines for your horses, they'll be fine. Permethrin has very low mammalian toxicity making it ideally suited for such applications and in fact is one of the if not the most commonly used active on food crops worldwide due to it's safe use record.
If you aren't able to keep them off the treated turf for seven days, you could apply the EXCITER PYRETHRIN. It has no residual meaning within a day you could let them graze over treated areas and they won't be in any danger. However, there are a few things to consider which in my opinion makes Permethrin the best choice. First, pyrethrin doesn't last long. Within a few hours of having been applied, it will be gone. Of course, this is why it might be well suited for your needs but when it comes to defeating pests, some residual is always better than none. Second, some mammals don't like pyrethrin. And though the chemical isn't a problem, it does irritate many people and animals making it impossible to use in some situations. Third, the price of pyrethrin is constantly going up and down. And though the first half of 2010 saw dropping prices, right now the world supply is limited and the price is rapidly going up. All these reasons point to Permethrin as being the better option when possible to use and since it has such a safe track record, ideal for use where horses and cattle roam.
Lastly, with gnats its important to expect to do a lot of treating to knock down the established population. In my experience, I've learned the best results will be achieved if you hit them hard and hit them often till you notice it start taking longer and longer for them to come back. That will be a sure sign you're winning the battle. Good luck!
Here are direct links to the information and products listed above:
Gnat Control Artilce: http://www.bugspray.com/catalog/products/page1801.html
Solo Back Pack Fogger: http://www.bugspray.com/catalog/products/page1824.html
Golden Eagle Fogger: http://www.bugspray.com/catalog/products/page1825.html
Permethrin 10: http://www.bugspray.com/catalog/products/page1817.html
Vegetables Plus Permethrin: http://www.bugspray.com/catalog/products/page1815.html
Exciter Pyrethrin: http://www.bugspray.com/catalog/products/page1816.html