| larval immersion tests with ivermectin in populations of the cattle tick rhipicephalus (boophilus) microplus (acari: ixodidae) from state of sao paulo, brazil. | larval immersion tests (lit) with commercial formulation of ivermectin were carried out with larvae of two field populations of rhipicephalus (boophilus) microplus from commercial dairy farms of the state of sao paulo, brazil and a susceptible strain (porto alegre) to differentiate resistant-suspected and susceptible strains. one of the populations tested (barra alegre) showed a lc(50) value significantly higher than the susceptible strain and a resistance ratio (ci95%) of 3.78 (3.47-4.12), lead ... | 2006 | 16904265 |