In Tick Management, Species Matters
In any part of the United States where ticks are present, awareness and personal protection are the first steps to avoiding tick bites and the potential disease pathogens they transmit: Using repellent and conducting frequent tick checks, especially after venturing into wooded or brushy areas, will help in avoiding ticks of all varieties.
But, for managing ticks more broadly, such as in yards and park spaces or at the community or regional level, the problem gets more complicated. No single method works perfectly, and one simple factor plays a key role in how well any particular tick-management method might work: Which tick species is it best suited for?
As part of a new special collection on Integrated Tick Management in the open-access Journal of Integrated Pest Management, Alexis White and Holly Gaff, Ph.D., of Old Dominion University have written a guide to tick control technologies that delineates their varying levels of effectiveness against the three dominant disease-carrying tick species in the eastern half of the United States: the blacklegged tick (Ixodes scapularis), the lone star tick (Amblyomma americanum), and the American dog tick (Dermacentor variabilis).
To the casual observer, a tick is a tick, but entomologists and public health professionals know different tick species behave in different ways.
“Most of the host-targeted methods … are tailored more toward one or two specific species of ticks because of tick-host preferences,” says White. “For example, lone star ticks are not known to feed on rodents, so bait boxes and tick tubes would not be an effective control measure for this species.”
Host-targeted methods aim to reduce the tick population by recruiting the animals that ticks feed on to the effort. For instance, bait boxes attract rodents and bring them into contact with acaricide (a tick-targeted pesticide), while tick tubes provide acaricide-laden nesting material for rodents. Both are tailored well to blacklegged ticks and American dog ticks, which commonly feed on rodents.
Lone star ticks, meanwhile, commonly feed on larger animals such as deer. A device known as the “4-poster” works similar to the rodent bait box, attracting deer with food placed in the center of four posts with rollers laden with acaricide that the deer rub against while feeding.
White and Gaff examined existing research on these tick-management methods as well as several others: habitat modification, controlled burns, broadcast acaricides, deer removal, deer fences, and even a semi-autonomous robot known as “TickBot” that lures ticks toward acaricide as it patrols a prescribed path.
“Based on current literature, broadcast acaricides consistently reduce human and domestic animal tick encounters at least for a short period of time,” says Gaff. “However, these chemicals are known to be harmful to other invertebrates in the environment and cannot be applied in all areas because of legal restrictions.”
For the typical homeowner in tick-prone regions, though, White says a few methods offer the best combo of practicality and effectiveness across species. “Our recommendation is for homeowners with property adjacent to woods to maintain regular mowing and leaf litter removal throughout the yard and also install a mulch barrier between the edge of their yard and the forest to serve as a reminder of the tick dangers along that edge,” she says.
In the course of their review of existing research, they noted that, due to its role as the primary vector of the bacterium that causes Lyme disease, the blacklegged tick has been the subject of far more research than other species. However, as the U.S. Centers for Disease Control and Prevention notes in a new report released Tuesday, both the volume and variety of tick-borne diseases is on the rise, with afflictions such as anaplasmosis/ehrlichiosis, babesiosis, Powassan virus, spotted fever rickettsiosis, and tularemia added to the list alongside Lyme disease.
Gaff says more research is needed, and integrated tick management (ITM) efforts must aim to employ a variety of practices to reduce the threat of tick-borne diseases.
“ITM needs to focus on creating areas with reduced tick populations rather than eliminating all ticks from the environment. Ticks do serve a purpose in the ecosystem, but we do not have to be their next blood meal,” she says.
Integrated Tick Management Collection, Journal of Integrated Pest Management