Host-dependent changes of four detoxification enzymes inTetranychus urticae. Koch were investigated in mites adapted to 14 plant species in 10 families. Relative to a snapbean-adapted mite strain, differences for aldrin epoxidase ranged from 0.4- to 1.5-fold,trans-epoxide hydrolase 0.5- to 1.5-fold,cis-epoxide hydrolase 1- to 3.4-fold, and α-naphthyl acetate esterase 0.4- to 2.4-fold. These host-related differences are much less than reported in other arthropods such as the Noctuidae. Hence, this broadly polyphagous mite may rely only in part on metabolic detoxification to protect it from toxic phytochemicals. Prospects of sequestering plant allelochemicals as an alternative defensive strategy are discussed.