Avaliação da eficiência do extrato de raíz Dahlstedti pentaphylla (Leguminosae, Papilionoidae, Millettiedae) sobre Boophilus microplus (Canestrini,1887) na Região do Vale do Paraíba - São Paulo, Brasil

Abstract

Laboratory and field trials were performed to evaluate the efficiency of Timbó root extract (Dahlstedtia pentaphylla) (Taub). Burk. (Leguminosae, Papilionoidae, Millettiedae) on samples of Boophilus microplus (Canestrini, 1887) in bovines of the Paraíba Valley region – São Paulo, Brasil. The “in vitro” trials were carried out using immersion of engorged females, and “in vivo” on bovines in the field by means of artificial infestation. The standard dilution was made from one part of root powder and three parts of ethanol this was considered the 100% solution. To determine the more efficient solvent to extract rotenone from the root, laboratory trials were conducted on B. microplus engorged females with in three solvents: water, ethanol a.p. and acetone a.p. The laboratory trials permitted the calculation of lethal doses at 90% (LD90) and 50% (LD50) for larvae between seventh and fourtheenth days of application and efficient concentrations at 90% (EC90) and 50% (EC50) on strain local and Mozo with B. microplus engorged females. For the larvae of the local strain (Paraíba Valley Regional Hub) LD50 calculated was 1:31,37 mL and LD90 was 1:85,24 mL. The EC90 for engorged females, of the same strain was of 1:10,19 mL and the EC50 1:34,94 mL. For the engorged females on the hypersersitive strain Mozo the EC90 was 1:23,91 mL and the EC50 1:60,46 mL. The mortality of engorged females in relation to the different kinds of solvents, was analyzed. In the field, the best results (76,10% of control) were obtained three days after application of the product extracted in ethanol, in 1:10, on animals. Then gradually between the seventh and fourteenth days the products lost efficiency, there was no significant difference between treatments and the control group after 21 days.