CHEMICAL UPDATE: Vertebrate Pest Controls
They're more clever than other pests and their appeal to human sentiment can create something of a public relations predicament. Vertebrate pests — rodents, birds and deer — can be incredibly difficult pests for landscape managers.
Dealing with vertebrate pests in urban environments poses special hazards. Pets are easily lured to poison baits and traps, and shooting is not permitted in cities. Plus, such animals are often classified as wildlife, which means they may have a “season” and may be regulated by state or federal wildlife agencies.
Non-lethal alternatives such as live traps, decoys and exclusion (fences) may be effective. Unfortunately, these tactics may be impractical or ineffective in many situations. Chemical repellents and anti-feedants are other tools that managers can employ.
Methyl anthranilate and anthraquinone are anti-feedants effective against Canada geese — by far, the most difficult bird pest. Other methods — herding dogs, dead goose decoys and sound cannons, to name a few — can be useful. However, bad-tasting antifeedants have been shown to be a reliably effective and non-intrusive strategy.
- Deer and rodents
Several substances can deter deer and rodent feeding through unpleasant odors or tastes. Castor oil is a common rodent repellent. Pepper (or capsaicin, derived from peppers), egg solids, the fungicide thiram, bitrex and several other substances also can reduce feeding through the unpleasant tastes or smells they impart.
Poison baits may be more suitable for rural settings. Interior rodent controls may also be registered for outdoor use where rats and mice may be a problem (around dumpsters, for example).
Deer and rodents can be amazingly persistent. Some animals apparently are able to overcome their initial aversion to certain products, especially when particularly hungry. And scientific research on repellents and antifeedants has shown mixed results. Frustratingly, what works in one situation may not work in another, sometimes for reasons that aren't clear. So be persistent and ready to employ a variety of strategies.
Aside from commercial products, stories abound regarding other substances for repelling animals. Soap, human hair and many other materials are frequently mentioned. In research, these materials may show some effectiveness, but tend not to perform as well as commercial products.
Sometimes, it's burrowing or some other destructive activity (such as with moles and gophers) that needs to be stopped, and the only solution may be removal of the animals. Trapping or lethal controls, if permitted, will be necessary.
Most vertebrate chemical controls have an EPA-approved label, which you must follow. This listing is for preliminary planning only and is not a substitute for label information. Remember to check local ordinances and state and federal laws governing wildlife.
The following list includes products — mostly repellents and anti-feedants, but also some poison baits — that are currently available. We do not rate efficacy here. Contact the suppliers using the information shown on the opposite page for more information.
For a comprehensive list of the Chemical Update tables that accompany this article, go to our Industry Research resource at .
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