Environmental variables serve as predictors of the invasive Asian longhorned tick (Haemaphysalis longicornis Neumann): An approach for targeted tick surveillance

Since the 2017 discovery of established populations of the Asian longhorned tick, (Haemaphysalis longicornis Neumann) in the United States, populations continue to be detected in new areas. For this exotic and invasive species, capable of transmitting a diverse repertoire of pathogens and blood feeding on a variety of host species, there remains a lack of targeted information on how to best prepare for this tick and understand when and where it occurs. To fill this gap, we conducted two years of weekly tick surveillance at four farms in Tennessee (three H. longicornis-infested and one without) to identify environmental factors associated with each questing life stage, to investigate predictors of abundance, and to determine the likelihood of not collecting ticks at different life stages. A total of 46,770 ticks were collected, of which 12,607 H. longicornis and five other tick species were identified. Overall, abundance of H. longicornis were associated with spring and summer seasons, forested environments, relative humidity and barometric pressure, sunny conditions, and in relation with other tick species. The likelihood of not collecting H. longicornis was associated with day length and barometric pressure. Additional associations for different life stages were also identified and included other tick species, climatic variables, and environmental conditions. Here, we demonstrated that environmental variables can be useful to predict the presence of questing H. longicornis and provide ideas on how to use this information to develop a surveillance plan for different southeastern areas with and without infestations.