Effects of barrier application of granular deltamethrin on subadult Ixodes scapularis (Acari: Ixodidae) and nontarget forest floor arthropods.

We evaluated the effects of a single application of granular deltamethrin made against nymphal Ixodes scapularis Say on the diversity and abundance of forest arthropods taken in pitfall traps in oak forest sites for 16 wk after treatment in central New Jersey. Control of I. scapularis subadults on treated plots ranged between 97 and 100% and continued at least 12 wk postapplication. Significant short-term changes in arthropod assemblages were detected at one of three study sites within 4 wk posttreatment. Effects were not distributed equally across taxa. Seasonal changes in numbers and diversity of forest arthropods in the study areas may have affected the impact of the acaricide in the treatment area. Comparison with control areas indicated that reductions in abundance of some arthropod taxa in the treatment area were detectable 12 wk after treatment. Total arthropod species diversity was not significantly affected by the application, and no treatment effects were detected 16 wk postapplication, suggesting that the arthropod community had recovered from the effects of the application. The merits of barrier applications in integrated tick control programs are discussed.