Spray and pour-on acaricides killed Tennessee (U.S.A.) field-collected Haemaphysalis longicornis nymphs Neumann (Acari: Ixodidae) in laboratory bioassays

Haemaphysalis longicornis Neumann (Asian longhorned tick) is an exotic and invasive tick species presenting a health and economic threat to the United States (US) cattle industry due to its ability to transmit pathogens and infest hosts in large numbers. The objective of this study was to determine if products RF2301 LPD PO (0.5% lambda-cyhalothrin, 2.5% piperonyl butoxide, 3% diflubenzuron), StarBar E-PRO (36.8% permethrin), and Prolate Lintox-HD (11.75% phosmet) applied as a spray and Y-TEX Brute (10% permethrin), Y-TEX Gard Star EC (40% permethrin), Martin’s FLY-BAN (7.4% permethrin), Martin’s Permethrin 1.0% (1.0% permethrin), and Martin’s Permethrin 1.0% Synergized (1.0% permethrin, 1.0% piperonyl butoxide) applied as a dip cause H. longicornis mortality. The efficacy of products was evaluated at label rates using H. longicornis nymphs collected from a cattle farm in eastern Tennessee in two different bioassays (spray or dip) against untreated controls. After exposure, ticks were transferred to clean petri dishes and checked for mortality at 0 h, 1 h, 2 h, 3 h, 4 h, 21 h, 24 h, and 48 h post exposure. No mortality occurred in the untreated controls, whereas all treated ticks were dead within 24 h of exposure (P < 0.0001). These findings support the hypothesis that currently available spray and pour-on products are effective at causing H. longicornis mortality. We conclude that these acaricides can be used as a component to prevent H. longicornis dispersal and for control in the US.