Three toxicological test methods were investigated for their practical value in testing a population of the two-spotted spider mite, Tetranychus telarius (L.), using Kelthane® (1,1-bis(p-chlorophenyl)-2,2,2-trichloroethanol), Meta-Systox-R® (O,O- dimethyl S-2-(ethylsulfinyI)ethyl phosphorothioate) and TEPP as toxicants. Mites were treated by a Slide Dip Method, a Cage Spray Method and a Leaf Dip Method. In terms of least variability the Cage Spray Method gave the best results at intermediate sensitivity followed by the Slide Dip Method which showed greater variability and the highest sensitivity. The Leaf Dip Method is characterized by the greatest variability and least sensitivity. By combination of different test methods differentiation between topical and topical plus residual effect of toxicants could be demonstrated. Similarly a strong inactivation of TEPP by the plant was detected. The Slide Dip Method and the Cage Spray Method appear well adapted for exact toxicological tests and tests on population dynamics. The Cage Spray Method is indispensable in cases where the survivors of a treatment are needed for further experiments as is the case in selection programs. The relatively small amount of work involved with the Leaf Dip Method makes it well suited for screening work, where a small variability is not essential.