The two-spotted spider mite Tetranychus urticae Koch is one of the economically most important pests in a wide range of protected crops worldwide. Due to its short life cycle, abundant progeny and arrhenotokous reproduction, it is able to develop resistance to these compounds very rapidly. Also, Tetranychus urticae is the most important pest of common bean (Phaseolus vulgaris) in Iran, and seedling stage is susceptible to the mite. Therefore, screening and using resistant cultivar of common bean is the most effective strategy to decrease mite damage. In order to finding seedling resistance ten cultivars of common beans (Naz, Dorsa, Akhtar, Pak, 65-062-107, 65-071-98, 65- 071-306, 65-071-410, 65-071-400, and 65-071-401) were selected to evaluate resistant mechanisms to two-spotted spider mite under growth chamber condition (25±3ºC temperature, 55±5% RH, 14:8 (D:L) h photoperiod, and 13000 Lux light intensity) in 2017 at Karaj, Iran. For evaluating antixenosis resistance,100 adult female mites were released in the center of platform with 40 cm diameter in which selected leaves isolated above and the pots located in the below of platform, and then the mites were counted after 72 hours. Antibiosis and tolerant test were studied by counting mite eggs after three weeks while, leaf damage scale was evaluated by 1 to 6 scoring. According to ANOVA analysis there was significant difference among resistance mechanisms. It was determined antibiosis mechanism was the most accurate test for evaluating of common bean resistance, and there were high correlation between antibiosis resistance and leaf thickness and abaxial trichome type. Finally, cluster analysis by Word method showed both of Naz and 65-062-107 were grouped as the most tolerant genotypes.
