Exploiting biology for management: Haemaphysalis longicornis and fermenting forage

Haemaphysalis longicornis (Asian longhorned tick, ALT) has become a pervasive pest in the United States, with initial discoveries in 2017 and a rapidly expanding range encompassing 21 states in the Eastern region of the country. ALT is associated with lowered productivity and growth of livestock, negative reproductive effects, hide damage, severe anemia, and transmission of pathogens such as Theileria orientalis (bovine theileriosis). Additional concerns arise from the parthenogenetic nature of ALT, which make it especially easy to spread with movement of livestock and feed. Present options for management are lacking; currently, producers are advised to mow and discard the forage in affected pastures and use acaricidal sprays on the field. This can incur a significant cost to the producer who will have to supplement the lost forage in affected pastures. Without the presence of ALTs forage is usually baled and stored, undergoing a fermentation process where temperatures throughout typically exceed ALT thermal maxima. If exploited, this could provide a novel means for managing populations without sacrificing valuable feed and would indicate if ticks can be transported in forage between sites. Experiments include lab trials performed in an incubator with varied humidity and temperature to replicate fermentation conditions and provide updated estimates of tick thermal maximums. We expect the fermentation process to cause significant mortality to ALTs and provide livestock producers with a means of managing tick infestations without significantly impacting production or transport of forage.