INTEGRATED MANAGEMENT STRATEGIES FOR AMBLYOMMA-AMERICANUM (ACARI, IXODIDAE) ON PASTURED BEEF-CATTLE

Data on tick control and knowledge of the damage caused to beef cattle by tick feeding were incorporated into a computerized dynamic life ta ble model (LSTSIM) for Amblyomma americanum (L.). Simulations were mad e to determine economically feasible, 5-yr integrated pest management (IPM) strategies for A. americanum in forage areas utilized by Bos tau rus, Bos indicus, and crossbred cattle (B. taurus x B. indicus). The e ffects of host resistance, pasture rotation, habitat conversion, topic al acaricides, systemic acaricides, and the area-wide application of a caricides to pastures on populations of parasitic female ticks were si mulated as individual control technologies and as components of multip le-factor IPM strategies. The most effective, single-factor control st rategy for A. americanum in beef cattle forage areas is the use of tic k-resistant B. indicus cattle. Pasture rotation combined with area-wid e acaricide applications was the only economically feasible IPM strate gy for B. indicus cattle and reduced tick densities by 89% after 5 yr. Thirteen economically feasible IPM strategies were identified for use with B. taurus cattle. Of these, the most efficacious was pasture rot ation in May combined with systemic or topical acaricide applications. Other strategies included systemic acaricides with area-wide acaricid e applications to pastures, topical acaricides with area-wide acaricid e applications, pasture rotation with habitat conversion and topical a caricides, and pasture rotation with habitat conversion, topical acari cides, and area-wide acaricide applications. Each technology reduced t ick densities on B. taurus cattle by >80% over a 5-yr period. Nine IPM strategies were economically feasible for use with crossbred cattle. Of these, pasture rotation combined with systemic or topical acaricide applications reduced the number of female ticks on cattle by >84%; pa sture rotation combined with habitat conversion reduced tick numbers b y 77%. The most effective nonacaricide-based IPM strategy for B. tauru s and crossbred cattle was pasture rotation combined with habitat conv ersion. No acaricide-free IPM strategy was economically feasible for u se with B. indicus cattle.