Simulation of rotational grazing to evaluate integrated pest management strategies for Boophilus microplus (Acari : Ixodidae) in Venezuela

Ranchers in Venezuela historically have controlled the cattle-fever tick, B oophilus microplus (Canestrini), with acaricide treatments of cattle but no technical planning. We developed a simulation model to evaluate cattle-tic k population dynamics in systematic pasture rotation systems and Integrated Pest Management (IPM) approaches to managing ticks in the tropical dry-for est ecological zone of Venezuela. Model output showed five generations of c attle-ticks produced each year throughout the dry and rainy seasons that oc cur in this zone. Sensitivity analyses showed dispropor- tionately large ch anges in on-host B. microplus populations in response to small changes in l arval mortality rates, such as those resulting from differences in the inna te resistance of cattle to tick parasitism, Simulation results with 1-6 pas ture systems suggest that adjusting the graze:rest sequence with systematic rotation among 4-6 pastures could suppress, but not eradicate, tick popula tions. (C) 2000 Elsevier Science B.V. All rights reserved.