Management of Haemaphysalis longicornis (Acari: Ixodidae) on a cow-calf farm in East Tennessee, USA.

Abstract

Haemaphysalis longicornis Neumann is an exotic and invasive tick species rapidly expanding across the United States. Large infestations of these ticks on cattle can cause anemia, and in eastern regions of the country, they are transmitting Theileria orientalis Ikeda within herds. Methods for managing H. longicornis in the environment are rarely successful and rely on chemicals. To document population effects from producer management decisions, we investigated the change in H. longicornis populations to different tick management practices chosen by producers at 3 different H. longicornis-infested farms. Farm 1 kept a closed herd, chose to cut brush monthly, used on-animal acaricides, and allowed us to drag weekly. Farm 2 kept an open herd, chose to cut brush yearly, did not use on-animal acaricides, and allowed us to drag for ticks weekly/monthly. Farm 3 kept an open herd, chose to cut brush yearly, used on-animal acaracides, and allowed us to drag for ticks monthly. We assessed H. longicornis populations responding to those methods over time using active surveillance methods at each farm. Management decisions on Farms 1 and 3 significantly reduced H. longicornis on farms. Importantly, Farm 1 management decisions reduced the chance of a tick being present by 90%; the number of questing ticks collected fell from 5,000 to 12 H. longicornis in 2 years. Therefore, combined management strategies such as keeping a closed herd, use of on-animal chemical control, mechanical control, and reducing the amount of vegetation on farms were effective ways for producers to manage Haemaphysalis longicornis Neuman (Ixodidae).