Rising floodwaters may force rats living along the river to seek shelter on higher ground, said Jim Pease, Iowa State University Extension wildlife specialist.

These rats may bring disease and other problems into homes. They are certain to cause destruction wherever they appear in the habitat of people, Pease said. However, business people and homeowners can prevent property losses and disease potential by exposing poison baits in places where rats are likely to gather.

Pease recommends using commercially prepared anticoagulant poisons in bait stations placed along the outside of walls of buildings to intercept invading rats. Such stations should have lock-down lids to protect children and pets. Warfarin, coumafuryl, pindone, brodafacoum and diphacinone are anticoagulants that are lethal to rats and are available under various brandnames.

Rats must feed on the bait for several consecutive days. Instructions for their use must be followed explicitly, Pease said. These are relatively safe chemicals and antidotes are available for pets or humans that accidentally take any of them. For use in wet places, cerealanticoagulant baits mixed with paraffin are available to prevent molding.

"Check bait stations every day and keep them supplied with fresh, clean bait," he said. One advantage of anticoagulant baits is that rats don't develop that "bait shyness" toward the anticoagulants. The anticoagulant poisons also are safer from the standpoint of pets.

Once a community has started a rat control program, Pease said, it should probably be continued even after the emergency has passed. Bait stations should be substantially built and located in various strategic places for year-round control.

Pease also suggests that homeowners take basic ratproofing measures such as replacing broken basement windows, making sure window screens are securely fastened and cleaning up any refuse that might attract pests.

Contact: Jim Pease, Extension Wildlife Specialist, (515) 294-7429, jlpease@iastate.edu

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