Tick. A harmless enough word when applied to the sound a clock makes, but when uttered in an outdoor context, the mere hearing of it can induce shudders.
For those of us in the green industry, the occurrence of these blood-feasting parasites is as routine as sunburn or muscle aches.
If a person wading through grass and shrubbery day after day didn’t encounter a tick from time to time, it would border on the miraculous. The fact that they are so common makes it tempting to dismiss them and the dangers they can pose.
According to Purdue University, an estimated 899 species of the genus Ornithodoros are found around the world, with some 90 found in the U.S. Not all ticks lurk in the grass. Several species are only found in animal nests, dens or caves. But there are still plenty of species that prefer the kinds of habitats where landscapers, lawn care professionals and arborists spend their time.
The life cycle goes like this: A larvae emerges from an egg and immediately seeks a bird or animal host. It feeds until fully engorged, drops off and molts into a nymph. It then seeks a second host, and after getting its fill of blood, drops off and molts into an adult. The third blood meal will be its final one, after which the female lays its eggs and dies.
Tiny so-called “seed ticks,” often thought of as a unique species, are just ticks in their larval stage. Ticks are arthropods, eight-legged creatures; with a magnifying glass, larvae can be distinguished from nymphs and adults by the presence of only six legs.
From a prevention and control standpoint, the same protocols will apply regardless of the species, but from a human health perspective, correctly identifying which species are present in an environment is important.
Ticks and human health
Of course, the worst thing about ticks is their role as vectors of disease-causing viruses, bacteria and protozoa. According to www.eXtension.org, a database of information from land-grant universities, Lyme disease is now present in 46 states and Rocky Mountain spotted fever in 40.
Those two maladies get the most ink, but they’re not alone: The U.S. Centers for Disease Control and Prevention lists a number of additional tick-borne diseases, including babesiosis, anaplasmosis, ehrlichiosis, Southern Tick-Associated Rash Illness, Heartland virus disease, Tick-Borne Relapsing Fever, tularemia, Colorado tick fever, Q fever and Powassan encephalitis.
Not all species of ticks carry every disease, so the specific risk depends on which species has bitten someone. Lyme disease, the most commonly diagnosed tick-borne illness, is only associated with two tick species: the blacklegged tick (also known as the deer tick), Ixodes scapularis, and the western blacklegged tick, Ixodes pacificus. Both of them can transmit anaplasmosis, while the deer tick can also transmit babesiosis.
Southern Tick-Associated Rash Illness is often confused with Lyme disease as the accompanying rash is similar to Lyme’s “bull’s eye.” Sufferers also experience headaches, fever and muscle aches. STARI is transmitted by the Lone Star tick, Amblyomma americanum. The bite of that particular species can also pass along a molecule that causes Alpha-gal syndrome, an allergy to red meat.
An unwelcome newcomer
It had been nearly a century since an invasive tick had shown up in the U.S., but as anyone who has dealt with or studied invasive plants and insects knows, it was only a matter of time. The Asian longhorned tick, Haemaphysalis longicornis, was confirmed in New Jersey in 2017, and since that initial discovery has been found in New York, Connecticut, Pennsylvania, Maryland, Virginia, West Virginia, North Carolina and Arkansas.
This species can reproduce asexually through parthenogenesis. It’s not only a threat to people’s pets but to the livestock industry, as a single animal can be infested with thousands of these parasites, leading to weight loss and anemia from the sheer loss of blood. It’s known to be a vector of human pathogens in its native range, but fortunately, so far no U.S. specimen has shown the presence of disease organisms.
Landscaping for tick prevention
Use these tips for tick-conscious landscaping your clients will thank you for:
1. Remove leaf litter.
2. Clear tall grasses and brush around homes and at the edge of lawns.
3. Place a 3-foot-wide barrier of wood chips or gravel between lawns and wooded areas to restrict tick migration into recreational areas.
4. Mow lawns frequently.
5. Stack wood neatly and in a dry area to discourage rodents.
6. Keep playground equipment, decks and patios away from yard edges and trees.
7. Suggest fencing to discourage deer, raccoons and stray dogs from entering yards.
8. Remove debris such as old furniture, mattresses or trash from yards, as they give ticks places to hide.
(Source: The Centers for Disease Control and Prevention)
Protecting your crew
There are things we can do to help keep ticks off ourselves and our crews, such as wearing long pants and light-colored fabrics while working. Ticks will gravitate toward those places where clothing grips skin the tightest, so tucking in pant legs and shirt tails will make it harder for them to find their way to ankles and waistlines.
The navel, groin, hairline, armpits, ears and the backs of knees are other spots on the body where ticks like to attach themselves. Encourage your employees to do a tick check on themselves in those body areas and their clothing after every shift. Removing ticks within 24 hours of attachment greatly decreases the chance of infection with a tick-borne microbe.
There are several repellent chemicals on the market, but permethrin is the ingredient of choice. It shouldn’t be applied directly to skin. Spray it on clothing according to the directions on the label or consider clothing that’s pretreated with it.
Janine Robertson, marketing and public relations manager at Insect Shield LLC, Greensboro, North Carolina, says of the company’s permethrin-treated apparel, “The protection stays on the clothing, not on your skin, and repels ticks, including those that can carry Lyme disease and other tick-borne illnesses and lasts for 70 washings.”
Permethrin is U.S. Environmental Protection Agency-registered, with no restrictions for use, and also protects against mosquitoes, ants, flies, chiggers and midges.
Insect Shield recommends using permethrin spray on boots. Ticks crawl upwards, Robertson says, so boots and socks offer great initial protection.”
Products containing 20% to 30% DEET (diethyltoluamide) are also effective, but some people are allergic to it. Picaridin, a pepper-derived alternative to DEET, has a lower toxicity and fewer occurrences of allergic reactions and has been shown to provide four to eight hours of protection. Botanical products such as oil of lemon eucalyptus or citronella may also have some value.
Many consider ticks as strictly a summer concern, but they can be active year-round. So don’t let your guard down when engaged in pruning or cleanups on warmer winter days.
Tick management in the landscape
Be aware that anywhere birds and mammals like to hang out, such as berry bushes or other wildlife-friendly plantings, ticks will probably be present too. Tall grasses, woodland edges and wood and brush piles are hot spots for tick populations as are locations with dense ground covers. If you offer tick management services to your clientele, such areas should be the focal point. It’s neither practical nor recommended to do a blanket treatment of an entire lawn or landscape.
“Everyone in our area routinely checks for ticks after being outside, particularly if we have been working in the woods or in pachysandra,” says Sean McNamara, manager of Redding Nursery in Redding, Connecticut. “I have found that pachysandra is the number one plant for picking up ticks in a yard.”
Ticks require lots of moisture and humidity, so practices conducive to increasing air flow and drying like mowing and removal of leaf litter make a landscape less hospitable for them.
A quick way to check for tick populations or to demonstrate their presence to your clients is to attach a 3-foot-by-3-foot sheet of white cotton, corduroy or flannel fabric to a pole and then drag it across tall grass and vegetation. The ticks will grab onto the fabric and can then be easily collected and identified.
Chemical treatment at the landscape level should focus only on those areas where pets or wild hosts are likely to frequent such as edges or fencerows. Bifenthrin, carbaryl, permethrin and pyrethrin are active acaricidal (tick-killing) ingredients that are often recommended, but before using any of them, consult with your state’s Cooperative Extension Service for specific chemical recommendations and the timing of applications for your region.
McNamara says, “We have a significant Lyme Disease problem in Fairfield County, and there are many companies here offering tick-spraying services with a trend toward ‘organic’ or ‘all-natural’ treatments. Though many people equate those terms with ‘safe’ and ‘nontoxic,’ our philosophy is that fewer sprays of a chemical are better than multiple sprays with less effective organic treatments, as every application even of supposedly natural products can still have a negative impact on beneficial insects.”
He adds, “We get good control of tick populations with just one or two sprays of a synthetic pyrethroid. This allows us to do a better job with fewer sprays than we’d have to do with an ‘all-natural’ formula. We feel this is a better value for the customer and better for the environment.”
Application timing is also very important, according to McNamara. Most of the spraying his crews do are at the nymph stage of the tick life cycle from mid-May through late June.
“This is the most dangerous time, as nymphs are very small and difficult to detect,” he says. “For our customers who get two sprays, we do one in April for overwintering adult ticks and a second in June for the nymphs. It’s very rare that we would do a third spray.”
Lab work Your local Cooperative Extension office should be the first point of contact for the identification of a tick species. If you, your employees or clients should find a tick attached to their skin, it’s a good idea to have it analyzed for any pathogens.
It’s good to have a solid understanding of what tick species are likely to be found in your area.
The University of Massachusetts, Amherst Laboratory for Medical Zoology can test ticks for more than 20 potential pathogens. Visit www.tickreport.com for instructions.
Another testing facility is Old Dominion University in Norfolk, Virginia.
Collected ticks can be frozen, bagged and mailed to either of these labs with an accompanying form and a fee. A report with information about any pathogens that were detected will be sent to you. Information is available at sites.wp.odu.edu/tick-team.
Anyone who spends time outdoors should be concerned about ticks. But they’re not something to panic about, nor should you make drastic changes to the environments they’re found in.
It’s good to have a solid understanding of what tick species are likely to be found in your area and what diseases they may carry, as well as the steps you can take to minimize the chance of getting bitten.
Even if tick spraying is not on your company’s menu of services, protecting yourself and your crews from exposure should not be ignored.
Phillip Meeks is an educator in the areas of natural resources, agriculture and horticulture. He resides in the mountains of southwest Virginia and can be reached at firstname.lastname@example.org.