full report of the project.
Ticks Drop in Maryland Control Program
By Judy McBride
May 25, 2001
Ticks that transmit Lyme disease have
been dropping like flies in parts of Maryland where deer snack on corn in
pesticide-treated feeders developed by Agricultural Research Service scientists in
Kerrville, Texas. To reach the corn, deer brush their heads and necks against
paint rollers filled with amitraz--an acaricide deadly to ticks but relatively
harmless to beneficial insects and wildlife.
Maryland is one of five northeastern states involved in a project to test
these feeders. ARS entomologist John F. Carroll at the
Henry A. Wallace
Beltsville (Md.) Agricultural Research Center and the other project
researchers in Connecticut, Rhode Island, New York and New Jersey aim to reduce
blacklegged tick nymphs at each of the 1,280-acre treatment sites by 90 percent
after five years. Its the ticks tiny, nymph stage that transmits
the Lyme disease bacterium to most people.
In 2000, two years after the feeders were deployed at three Maryland test
sites, blacklegged tick nymphs had dropped 59 to 71 percent, according to
Carroll. He anticipates reductions of at least 75 percent after two more years.
In the Northeast, the blacklegged tick has a two-year life cycle.
While tick nymphs are most dangerous to humans, the four-poster feeder
targets female adults--before they can lay the eggs that will hatch into larvae
that develop into nymphs. A female tick can lay up to 3,000 eggs in her
lifetime but rarely passes on the Lyme disease pathogen to her offspring.
Generally, the larvae--before they become nymphs--pick up the pathogen from
feeding on infected mice or other small animals.
In the spring of 1998, Carroll and colleagues set out 25 feeders at the
Beltsville center and at each of two other sites located near Baltimore where
deer and tick populations are high. The researchers keep the feeders stocked
with corn and amitraz in spring and fall, when adult blacklegged ticks look for
a blood meal. Nearly all female ticks feed on deer.
ARS is the U.S. Department of
Agricultures chief scientific research agency.
Scientific contact: John F. Carroll, ARS
Epidemiology and Systematics Laboratory, Beltsville, Md., phone (301)
504-9017, fax (301) 504-5306, email@example.com.