Tetranychus urticae is a polyphagous species. You can rear and test them e.g. on bean (Phaseolus vulgaris) plants in green house. Regarding T. urtucae you can find a lot of references. Please, write into Google e. g. Tetranychus urticae, pesticides, acaricides. I do not understand what do you mean on agressivity of T. urticae? T. urtcae has great colonies on plants, they are easy to sample.