ABSTRACT
Laboratory trials were performed to evaluate the efficiency of Timbo 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, Brazil. The trials were carried against engorged females and larvae. The standard dilution was made from one part of root powder and three parts of ethanol, which was considered the 100% solution. To determine the most efficient solvent to extract rotenone from the root, laboratory trials were conducted on B. microplus engorged females with 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 the seventh and fourteenth days of application and efficient concentrations at 90% (EC90) and 50% (EC50) on local strain and Mozo strain of B. microplus engorged females. For the larvae of the local strain (Regional Polo of Paraíba Valley) calculated LD50 was 1: 231.37 mL and LD90 was 1: 85.24 mL. The EC90 for engorged females of the same strain was 1: 10.19 mL and the EC50 1: 34.94 mL. For the engorged females on the hypersensitive 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 solvent was analyzed.
KEYS WORDS:
Boophilus microplus, control; plant extract; Dahlstedtia pentaphylla, rotenone.