Using a particular rodenticide for controlling prairie dog populations is now a federal offense in four states.
In August, the Environmental Protection Agency announced the agency had signed off on a proposal from the rodenticide's manufacturer, Liphatech, to amend its EPA registration of Rozol Prairie Dog Bait (EPA Reg. No. 7173-286) so that the rodenticide could no longer be used in Montana, New Mexico, North Dakota, or South Dakota.
Rozol is one of several rodenticides containing chlorophacinone as an active ingredient. The EPA still approves use of the product to control populations of black-tail prairie dogs in Colorado, Kansas, Nebraska, Oklahoma, Texas, and Wyoming.
(Courtesy of the U.S. Fish and Wildlife Service)
The product is a restricted-use pesticide, which, according to its label, can be used only during certain times of the year and must be applied at least six inches down in active prairie dog burrows. No bait is to be left on the soil surface, and any bait spilled above ground or placed less than six inches down burrow entrances must be disposed of properly. After placing the bait, the applicator must return at least twice at specified times to retrieve and properly dispose of any bait or dead or dying prairie dogs that may have come to the surface. Doing so helps prevent toxicoses in nontarget species.
In 2009, the World Wildlife Fund petitioned the EPA to suspend its registration of Rozol Prairie Dog Bait and cancel certain application sites for the product because the rodenticide was a threat to nontarget species, including endangered animals.
One such federally protected species threatened by Rozol is the black-footed ferret, which preys on prairie dogs and uses their burrows for shelter.
When the EPA issued a call for public comments on the WWF petition in 2009, the AVMA wrote in support of the organization's position. The Association recognized the availability of safer yet effective alternative control measures and cited AVMA policies relating to the prevention of toxicoses in wildlife and the conservation of wild and exotic animals.
While recognizing that black-tailed prairie dog populations in some areas may be problematic and that control methods have varying degrees of success, the AVMA, like the WWF, was concerned about the unintended consequences of using an anticoagulant rodenticide as a prairie dog bait.
"The use of Rozol (chlorophacinone, an anticoagulant) as BTPD bait is concerning because of secondary exposures, intoxications, and deaths of non-target species, including endangered species," the AVMA wrote.
The AVMA also noted the Montana Department of Agriculture's position that other rodenticides are available that accomplish the same goal when used properly and are less hazardous for nontarget species than anticoagulants.
The EPA action was effective Aug. 8. Among the provisions, no person may sell or distribute existing stocks of Rozol Prairie Dog Bait in Montana, New Mexico, North Dakota, or South Dakota unless, for each such transfer, a copy of the final EPA cancellation order accompanies that transaction.
For more information, go to www.avma.org and enter "Rozol Prairie Dog Bait" in the Search AVMA field.