An urban roof rat control program in Orange County, California

A program to control roof rats (Rattus rattus) has been conducted by the Orange County (CA) Vector Control District since 1975. Located in southern California just south of Los Angeles, urbanization takes up about ½ the total area of the county, and it is mainly a semi-desert situation with <15 inches which is used by rats as harborage and s a food source. The roof rat is a difficult animal to control. Our program is basically a complaint/response program; we have tried neighborhood surveys and inspections and found them not to be cost-effective. When we receive a service request, a technician visits the property to inspect for rat sign, harborage, food sources, and entrances into structures. The technician provides the landowner with written recommendations and an educational pamphlet. With the landowner’s permission, rodenticide bait, if needed, will be placed on the property by the technician; however, it is the owner’s responsibility control rodents within a residence himself or by hiring a pest control operator. The program emphasizes public education, environmental management, and chemical control. The program also conducts ectoparasite and disease surveillance; however, if fleas are rare or absent on roof rats, then in most cases there is little justification for rat control to be done by a public agency