Acaricide susceptibility of immature Ixodes scapularis (Acari: Ixodidae) as determined by the disposable pipet method.

The disposable pipet method was used to establish baseline dose-mortality data for immature stages of Ixodes scapularis Say for carbaryl, esfenvalerate, cyfluthrin, and permethrin. Permethrin and cyfluthrin were most toxic to both nymphs and larvae, followed in order by esfenvalerate and carbaryl, based on LD50 and LD90 values. Larvae were substantially more susceptible than nymphs to each compound.