Control of the American dog tick, Dermacentor variabilis Say (Acarina: Ixodidae)

In a 4 ha area, of which 1/3 was meadow vole habitat, the old vole runways were spot treated in early spring with a 1 per cent spray of flowable Sevin(R) 4 F (42 per cent AI) on ca 4 m centers. New runways, a noted, were treated in June. The application averaged 60 ml of Sevin(R) 4F/ha. The spring adult cohort of Dermacentor variabilis was below 10 per cent of that usually expected. These adults had been exposed to this treatment the previous year as spring larvae and summer nymphs. The reduction of the adult population occurred in a season of heavy infestation. This treatment is not labor intensive and requires only a minimum of pesticide because it is directed to its target, the attached immatures, by the behavior of the field mice. It should be noted that all the small rodent hosts of the immatures use the vole runways