Survival analysis of Rhipicephalus microplus larvae treated with coumarinic derivatives.

Rhipicephalus (Boophilus) microplus represents one of the greatest challenges for livestock production in tropical and subtropical regions. Its control has been based on the use of synthetic chemical acaricides, which has led to the development of resistance to active ingredients belonging to the pyrethroid and organophosphate groups. Therefore, the search for new compounds with acaricidal potential is a priority in the control of ticks in cattle. This study evaluated the effect of different concentrations of coumarin derivatives (CD) on the survival of R. (B.) microplus larvae by larval bundle testing. The data obtained were analyzed using the Cox proportional hazard model. A reduction in larval survival was observed with coumarins that had methyl substituents in the R4 or R7 positions, especially C12, while an opposite effect was detected with chloromethyl substituents in R4 or isobutyl in R3. These findings highlight the potential of coumarin derivatives in the development of new strategies for tick control and the management of resistance to conventional acaricides.