University of Vermont
Department of Plant and Soil Science

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AVOID LYME DISEASE WHILE GARDENING

Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont

Lyme disease is a potentially disabling disease of joints and the nervous system, spread by deer ticks.  Knowing about this disease, how it is spread, and steps to avoid it, will allow you to continue gardening or enjoying the outdoors, along with your pets, without concern for these spider relatives.     

This previously unknown disease was first found on children in Lyme, Connecticut in 1975.  It was given its current name, ticks were identified as the vector spreading it, and in the early 1980’s research identified the cause as a spirochete bacterium.  It has since become the most reported vector-borne disease in the country.  It is prevalent in the Northeast, and parts of the upper Midwest, with reported cases in most every other state.  While Pennsylvania, the Hudson Valley of New York, and southern New England areas are high risk, much of the rest of New England is moderate risk with only the most northern parts low risk.

Although this disease is rarely fatal, it can cause debilitating illness including heart irregularities, facial paralysis, and impairment of the nervous system.  Early symptoms to watch for include minor symptoms such as skin rash, fever, headaches, and muscle and joint pain.  Very characteristic, but not always present, is a skin rash called “erythema migrans”.  This rash appears as a red circular patch at the site of a tick bite within three days to one month.  As it enlarges, this patch often takes on a “doughnut” or “bulls eye” appearance. 

As ticks like warm spots, parts of the body to watch are thighs, groin, trunk, scalp, and armpits. Ticks don’t fly or jump, so you must come in contact with them and they crawl once on a body.  Ticks are generally present within 18 to 24 inches of the ground.

Although there are no vaccines to prevent Lyme disease, it can be treated with antibiotics once diagnosed.  Prompt treatment, however, is important.  Early treatment usually results in full and rapid recovery.  Permanent damage may occur if treatment is in the very late stages.

Three types of ticks can carry Lyme disease, but the deer (black-legged) ticks spread this in the Northeastern and North Central states.  Ticks feed on small rodents, birds, and deer that may carry the Lyme disease but not be affected by it.  This is where the ticks pick up the bacterium, and then transmit it to humans. 

Although deer are what most think of as carrying ticks, field mice in many cases may be spreading them more widely.  Opossums aren’t usually thought of regarding deer ticks, but they’re a huge help with them.  As most mammals wandering through grass and brush, they attract ticks but, being very effective groomers, they kill 95 percent of ticks that try to feed on them. 

Obviously, avoiding places where ticks live or checking for tick bites if you are in such areas is a primary means of prevention of Lyme disease.  Ticks like cool, wet places such as wooded areas, piles of debris, stone walls, and high grasses.  If you garden in or around such areas, be particularly watchful for ticks and tick bites.  Any other activities in such areas are also at risk, such as camping, hiking, fishing, hunting, or walking pets.

Since a deer tick must remain attached for 36 to 48 hours to cause infection, frequent checking for ticks is important.  Both the nymph and adult stages of deer ticks can transmit Lyme disease.  Nymphs are most active from mid-May to mid-August, while adults (the size of poppy seeds) are most active from March to mid-May and from mid-August to November.     

If you find ticks, remember not all carry this disease.  Recent surveys in Connecticut revealed that about one-third of deer ticks carried Lyme disease, while about one-half of deer ticks in Vermont were infected. Even better news is that in Vermont, less than ten percent of ticks carried another of the serious tick-borne diseases—primarily anaplasmosis and babesiosus.

Half or more of tick bites cause an allergic reaction, but all such symptoms shouldn’t be confused with the symptoms of Lyme disease.  Such non-serious allergic reactions appear within a few hours or days, do not expand or have the bulls-eye feature, and disappear within a few days.  Infections from Lyme disease usually start out about two inches wide, then expand.  If the red area from a bite is under the size of a quarter, this is likely not Lyme disease and should disappear soon.

Unless you happen to feel a tick moving, or actively look closely for them (unless a family member or friend is nearby, a handheld mirror can be handy to check backs), you may not find them.  Their saliva may act as an anesthetic so their prey doesn’t feel them.  Unlike mosquitoes which “bite” and move on, ticks attach for several days of feeding.  Their feeding parts contain barbs which make them difficult to remove, as does a cement-like substance they can secrete.

No matter what kind of tick you find, deer or otherwise, you probably want to remove it.  DO NOT try to remove it with heat as from a match, or alcohol.  This will only irritate the tick and cause it to more quickly insert more toxin.  Instead, use a pair of fine-tipped tweezers to grasp the mouthparts of the tick as close to the skin as possible, and firmly pull straight out.  Fine-tipped is important, rather than normal tweezers that will simply squish ticks.  Best to use is an inexpensive tick removal tool you can find at most drugstores.

Tips to prevent tick bites, in addition to avoiding their habitats, include:
--Wear light-colored clothing so you can spot ticks more easily.
--Wear long-sleeved shirts and pants to minimize exposure.
--Tuck pant legs inside socks or boots to keep ticks on the outside.
--Use an insect repellent containing 20 to 30 percent DEET, 10 percent for children, or picaridin.  Most effective at killing ticks is permethrin, but only use this on clothing as it becomes ineffective on skin.  Clothes sprayed with the latter will remain effective for up to two weeks if not washed.  If not washing treated clothing, keep in plastic bags in between wearing.
    You also may find any number of repellents based on essential plant oils.  Recent research (www.cdc.gov/lyme under prevention/natural repellents) showed effectiveness of several such oils such as from rosemary, garlic, lemongrass, geranium, and others.  
--After being outdoors in high risk areas, inspect body surfaces closely.  Place clothes in a hot drier to kill any ticks if on clothes.

About 70 percent of people that contract Lyme disease catch it from ticks in their own yards.  Tips to minimize ticks in your landscape include:
--Keep your yard clean and free of debris, grass clippings, and leaf litter.
--Keep grass mowed, especially along property edges.
--Trim shrubs near walks and patios, and keep groundcovers away from these and play areas.
--Create a three-foot wide barrier, three inches deep, between lawns and wooded areas using gravel, mulch, or wood chips.
--Keep woodpiles away from gardens and lawns.
--If you have deer nearby, or visiting your landscape, begin deer-proofing techniques.  There are some articles on this on my website (perrysperennials.info).

While one of the original web resources for tick information was from the University of Rhode Island (www.tickencounter.org), many states now have excellent resources too, as does the National Centers for Disease Control and Prevention (www.cdc.gov/ticks). 


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