Blacklegged ticks are also known as deer ticks because the white-tailed deer is the main host of their adult reproductive stage. The blacklegged tick is widely distributed across the eastern United States and has been expanding into southeastern Canada. The western blacklegged tick occurs along the U.S. Pacific coast into southern British Columbia. Both blacklegged ticks are vectors of Lyme disease.
Most Lyme disease cases are reported from the Upper Midwest and northeastern states and their bordering areas of Canada. In these areas, immature blacklegged ticks prefer to feed on white-footed mice, the primary reservoir for Lyme disease. Western blacklegged ticks and blacklegged ticks in southern states feed as immatures on other small animals as well that may not be Lyme disease reservoirs or are not as abundant as white-footed mice.
Since tick-borne diseases usually peak in June and July of each year, treatments applied in May are most likely to reduce disease transmission. Treatments for blacklegged ticks should be focused along the perimeter of properties, 10-15 feet into wooded areas and 2-3 feet into lawns, as well as to shady plant beds. Granular or high-volume spray applications are best for penetrating vegetation and leaf litter where blacklegged ticks prefer to live to maintain moisture.