Q. I have lived in Pittsburgh my entire life, gardening and hiking in our county parks. For the first time in my life, I am finding ticks on myself when I return from hikes or spending time in my yard. I am concerned about Lyme disease and was wondering if there were any steps I can take to control them in my yard.
A. Other parts of the country -- the New England states, parts of Minnesota and Wisconsin, and the Upper Peninsula of Michigan -- have been dealing with abundant tick populations and Lyme disease for much longer than we have in Western Pennsylvania. Lyme disease takes its name from the town of Lyme, Conn., where the disease was first identified in the mid-1970s.
Unfortunately, it seems that our reprieve from this pest is over. People who work outdoors or who spend a lot of time playing in Western Pennsylvania's natural areas will need to take steps to protect themselves and their four-legged friends from blacklegged ticks to minimize the chance of contracting Lyme disease. There are other species of ticks found in Western Pennsylvania, and while they may not carry Lyme disease, there are other equally serious diseases that ticks can transmit to you and your pets.
Tick-borne diseases have been on the increase across the United States. A number of factors contribute to the problem, including:
• Increased building in wooded areas, which increases the chance for contact with ticks.
• Increased tick populations.
• An overabundance of deer.
Lyme disease is caused by a bacterium, Borrelia burgdorferi, and is transmitted to people, companion animals and wildlife by the blacklegged or deer tick (Ixodes scapularis). Blacklegged ticks have a two-year life cycle, starting with females laying eggs in mid-late spring. Larvae hatch in early summer and attach to small mammals, such as mice and chipmunks or birds to feed, then drop off to molt into nymphs that will be active the following spring. Larval activity peaks in late summer. Nymphs are active the following May, June and July. They also attach to small mammals or birds, then molt into adults after feeding.
White-footed mice (Peromyscus leucopus) are an important host for the larval and nymphal stages of blacklegged tick, and they are also a primary host for the bacterium that causes Lyme disease. After larvae and nymphs feed on infected mice, they become carriers of the bacterium. Adult blacklegged ticks become active in fall and remain so on warm winter days and again the following spring. They attach to white-tailed deer to feed. Adult males die after mating, and adult females die after laying eggs. Although deer are not a source of the bacterium, they carry adult ticks into your yard where the females will lay eggs, increasing the number of tick larvae and nymphs there. The nymph stage is most likely to transmit Lyme disease.
Blacklegged ticks are most abundant in densely wooded areas and the edges of woods; ornamental plantings and lawns are less attractive to them, except where they abut the woods. There are a number of landscape management practices that can make your yard less suitable habitat for ticks. If you have a very large yard, consider managing the portion of it your family uses most to minimize tick habitat, including walkways, patios, play areas, gardens and service areas (sheds, trash cans, etc.). These practices include:
• Clean up piles of brush, fallen leaves and remove weeds and brushy growth at woodland edges.
• Keep the grass mowed regularly through the growing season.
• Restrict the use of ground covers such as pachysandra in areas used heavily by the family and pets.
• Discourage rodent activity by keeping grass, brush and weeds trimmed, cleaning up leaf piles and sealing stone walls.
• Exclude deer from your yard through the use of fencing and deer-resistant plantings. Avoid feeding birds near the house because deer (and mice) are attracted to bird feeders, especially in winter. Excluding deer reduces the number of egg-laying adult ticks brought into your yard.
• Move children's play sets and sand boxes away from woodland edges. Use hardwood mulch around swing sets and sand boxes rather than grass or other vegetation.
• Hire an arborist to thin the crowns of shade trees and limb them up to allow more sun in and to reduce humidity, which makes an area less attractive to ticks.
• Create borders at woodland edges and around stone walls with wood chips or gravel. Three feet or wider borders are most effective.
• Use labeled acaracides as a targeted barrier treatment around the perimeter of areas used most by your family. Active ingredients used to control ticks in the landscape include bifenthrin (Ortho Home Defense Max), cyfluthrin (Bayer Power Force Multi-Insect Killer), lambda-cyhalothrin (Spectracide Triazide Concentrate), and permethrin (Bonide Eight Insect Control). Read and follow all label directions for most effective control and safety.
In addition to landscape alterations, remember to protect yourself and your family by wearing long pants tucked into light-colored socks (ticks will crawl up your legs!) and closed-toe shoes when working or playing in your yard or hiking in the woods. Light colored clothing makes it easier to see ticks because larvae are about the size of the period at the end of this sentence, and nymphs are not much bigger. DEET or permethrin-based repellents, used according to label directions, provide the best protection from ticks of all kinds. Protect your four-legged friends with products your veterinarian can recommend to keep them from bringing ticks into your home and to protect them from Lyme disease -- They are susceptible, too.
First Published: March 31, 2012, 4:00 a.m.
