A method is described to test individually and in combination the effects of different chemicals on the adult survival and oviposition ofTetranychus urticaeKoch. Materials in water formulations were sprayed on the leaves ofVicia fabaL. and tests with 5 females on excised leaves lasted for one day. Various spray adjuvants acted as ovipositional repellents but did not reduce oviposition when only treated foliage was available. S. M. 134 killed adults and prevented oviposition. The most effective innocuous materials are: Aerosil 200, oleoresin of capsicum, extract of juniper berry, levulinic acid, pumpkin and rapeseed oils, sinigrin, sodium silicate, and thiodiglycol. A 0.03% carbaryl:0.27% Arogen® 500 combination had no effect, whereas a combination with 0.06%:0.54% of these components respectively reduced adult survival and oviposition; a 0.05% formulation of phosmet had no effect, whereas a 0.05% phosmet:0.45% Zeolex® 100 combination reduced adult survival and oviposition; and a 0.1% pirimiphos-methyl:0.9% Arogen® 500 combination was less effective than 0.05% of Pirimiphos-methyl alone and about equal to a 0.05% Pirimiphos-methyl:0.45% Arogen® 500 combination. The effectiveness of pesticide-silica combinations depends on the concentration of components and type of silica.