essential oils from the leaves of bauhinia rufa and b. dumosa collected from the cerrado biome in central brazil were obtained by hydrodistillation and analyzed using gc and gc/ms. both oils had a predominance of sesquiterpenes (b. rufa: 95.3 +/- 0.5%; b. dumosa: 97.2 +/- 1.1%). -caryophyllene (15.8 +/- 0.5%), epi--cadinol (12.8 +/- 0.4%), -muurolene (12.2 +/- 0.4%) and -cadinol (10.0 +/- 0.5%) were identified as the major constituents of the b. rufa oil, whereas germacrene b (37.6 +/- 1.2%) and (e)-nerolidol (29.1 +/- 0.6%) were the major constituents of the b. dumosa oil. both oils were toxic to tetranychus urticae by fumigation (b. rufa: lc50 = 2.76 ul/l of air; b. dumosa: lc50 = 0.97 ul/l of air) and residual contact (b. rufa: lc50 = 30.46 ul/ml; b. dumosa: lc50 = 16.44 ul/ml). the results of the two-choice method revealed that the oils affect the behavior of the mite, interfering in its feeding and egg-laying preferences.