Studies have shown that, in areas where black-legged ticks are abundant, some 70% of people infected with the Lyme disease spirochete are bitten by ticks in their yard. In such areas, where ticks are abundant on residential properties, where there are high infection rates of ticks with spirochetes, and a lack of feasible alternative control strategies, pesticide applications may be an effective means for reducing black-legged and other ticks.
The use of pesticides for tick control should be considered as a final alternative to the preventive measures discussed above, and only after the presence of ticks has been documented.
Many acaricides available for tick control can be purchased and applied by the general public. Read and follow all directions on the label. Alternative acaricides include soaps and desiccants. Specific acaricides, formulations, and methods of application may be restricted to certain target areas. Users are cautioned to carefully read the acaricide labeling to ensure that the proposed application is not in violation of federal and state pesticide control laws. Contact Rutgers Cooperative Extension, your County Agricultural Agent, or pesticide dealer for recommendations. The New Jersey Agricultural Experimental Station publishes recommendations for pesticide use against ticks. Pesticides come in both liquid and granular form. Both have various advantages and disadvantages. Generally, granular formulations are easier to apply by the homeowner. Application of liquid formulations requires access to large amounts of water and sophisticated equipment. However, less acaricide is required to achieve adequate control. Consideration should be given to hiring a professional pest control firm, which has the necessary experience and equipment to perform tick control.
Research has demonstrated the effectiveness of properly timed acaricide applications. If ticks are present, treat edge areas of the property (where turf grass and woods meet) plus 12 feet into the woods to create a protective barrier. Shady areas of the lawn adjacent to the woods and areas landscaped with shrubs and ground covers such as pachysandra may also be treated.
Adult black-legged ticks are the easiest stage to control. They seek hosts on shrub layer vegetation in the fall and spring. Applying liquid acaricide during this period can result in control exceeding 95%. However, reduction of the adult population does not offer the same public health benefits as the control of nymphs, the life stage responsible for the majority of disease transmission.
Controlling black-legged tick nymphs is crucial, but more difficult since they are most active when foliage is present. Successful control of nymphs has been achieved using either granular or liquid formulations of a variety of acaricides. Granular acaricides, which can penetrate into dense foliage, can be applied with a chest-mounted cyclone spreader. Liquid formulations should be applied with sufficient pressure to penetrate foliage and physically disturb leaf litter. Although control exceeding 90% can be achieved with a single, well-timed application made in late May to early June, such applications will not prevent the emergence of larvae in the summer or the appearance of adults in the fall. Further, these applications appear to be less effective on lone star nymphs and adults, which may coexist in the treated area. Control of black-legged tick larvae is generally not recommended because this stage is not infected with the Lyme disease spirochete.
Liquids should be allowed to dry thoroughly before humans or pets reenter the area. Be especially careful using such materials near bodies of water - do not contaminate water. Wear gloves and eye protection and do not eat or smoke when applying any pesticide. Wash skin and clothing after application, and always launder pesticide-contaminated clothing separately. Carefully read and follow all product directions.
Acaricides should only be used if avoidance of tick-infested areas is not an option and ticks are known to occur in the area to be treated. Since no tick control method is 100% effective, personal protection should always be practiced. Use of any chemical tick control method has limited or unpredictable success in reducing black-legged tick populations when used alone, particularly in residential settings. Consider using chemical control only in concert with habitat modification measures. Applications of either liquid acaricides, using high pressure hydraulic sprayers, or granular formulations, which can penetrate into dense foliage, directed against black-legged tick nymphs in late May to early June appear to have the greatest impact on the tick population, thereby reducing exposure to tick-borne diseases. Single applications consistently resulted in control of greater than 90% of nymphs. There is no need for repeated applications at regular intervals during the summer. However, the effectiveness of a single control attempt directed solely against adult or nymphal ticks in small areas will be temporary and limited only to that stage.
Research on control of ticks is ongoing. Workers have shown that by using registered insecticides at the proper time, tick contact may be greatly reduced. Treating with an insecticide does not guarantee, however, that no ticks will be present. People still need to protect themselves by dressing appropriately, using repellents when in potentially tick-infested areas and checking daily for the presence of ticks (and removing them if found).