The only toxicant federally registered for muskrat control is zinc phosphide at 63.2% concentrate. This formulation is a Restricted Use Pesticide used in making custom baits. Zinc phosphide baits for muskrats generally are made by applying a vegetable oil sticker to cubes of apples, sweet potatoes, or carrots; sprinkling on the toxicant; and mixing thoroughly. The bait is then placed on floating platforms in burrow entrances or on feeding houses. Always use caution when mixing and applying baits treated with zinc phosphide. You must read, understand, and carefully follow all label instructions on the zinc phosphide container before using.
Some states have obtained state registrations for use of anticoagulant baits such as warfarin, diphacinone, and chlorophacinone. These materials have proven effective, species selective, practical, and environmentally safe in field applications to control muskrats. Apparently, there is not sufficient demand or research available to consider federal registration of anticoagulants for muskrats. These same first-generation anticoagulants are, however, federally registered for use in control of commensal rodents in and around buildings and for some use in field situations for rodent control.
Use of the anticoagulant baits, where registered, is in the form of a paraffinized “lollipop” made of grain, pesticide, and melted paraffin. It is placed in burrows or feeding houses. The anticoagulant baits also can be used as a grain mixture in floating bait boxes.
No fumigants are currently registered for muskrat control.
Resources: (online)
Muskrats
