Abstract: Effects of Malus pumila Mill., Sambucus williamsii Hance, Melia azedarach L. and Rhus typhina L. on the development and fecundity of Tetranychus urticae Koch were investigated by means of leaf disk rearing method. Kjeldahl method, Soxhlet extraction method, Anthrone colorimetry, and Folin-Denis colorimetry were also applied to measure the contents of nitrogen, crude fat, soluble sugar and tannin, respectively. The results showed that M. pumila and S. williamsii with high content of nitrogen (2.98% and 4.00%, respectively) and soluble sugar (19.92% and 12.81%, respectively) were suitable for the development and fecundity of T. urticae. R. typhina with the lowest content of nitrogen and soluble sugar and the highest content of tannin (11.45%), however, was baneful to T. urticae. Therefore it can be concluded that tannin, as the secondary compound of plants, may play important role in resistance of plants to mites.

Key words: Tetranychus urticae, Malus pumila, Sambucus williamsii, Melia azedarach, Rhus typhina, nutrient substance, tannin, mite resistance