The detached-leaf technique has long been used in plant disease studies. In this research, the technique was used on dry bean (Phaseolus vulgaris) leaves detached and cultivated in vermiculite to study the resistance of bean cultivars to different populations of bean rust (Uromyces appendiculatus) collected from different regions on different dates. The symptoms expressed by the whole plant were compared to those expressed on detached leaves. The lesions types in detached leaves were analogous to those on intact plants. The cultivars Aporé, Novo Jalo, and Corrente were resistant to all populations of the pathogen. The detached-leaf cultivated in vermiculite technique exhibited advantage in relation to other techniques for resistance evaluation. This technique permits the retention of more leaves in the same recipient, facilitates evaluation of more cultivars besides the economy of space and convenience in conducting the work.
