Proceedings of the Vertebrate Pest Conference

A detailed description of problems of Norway rat infestation of sanitary sewer systems is provided, as well as a review of control methods and materials. Design and maintenance of urban sewer systems can reduce rat problems, but ongoing effective rat control programs typically must include use of rodenticides. Commonly used active ingredients are discussed, as is the formulation and application of baits appropriate for use in sewer systems. The need for prebaiting when using acute toxicants is noted, as is the desirability of including mold inhibitors into bait formulations when using paraffin baits or anticoagulant baits, which require repeated feeding to be lethal. A method for locating rodents burrows that are connected to main sewer lines or laterals is described, using smoke bombs and portable blowers to force smoke through sewer systems and reveal locations where rats have points of access. Components of an effective strategy to control Norway rat infestations in sewers are discussed, and literature citations are provided.