Five faba bean genotypes partially resistant and susceptible to Botrytis fabae were used at the laboratory to follow the effect of the temperature and the concentration of the inoculum on the expression of four components of partial resistance. The incubation period was longer at 5 degrees C and appeared significantly shorter from 10 degrees C to 25 degrees C but did not allow a good discrimination between the genotypes. The area under disease progress curve (AUDPC) of the lesion size increased from 5 to 25 degrees C with significant differences between the genotypes especially starting from 15 degrees C. The latent period decreased and spore production increased from 10 degrees C to 20 degrees C but were expressed only at 20 degrees C and 25 degrees C. The size of the lesions and the number of spores increased and the latent period decreased with increasing the inoculum concentration. The inoculation by 2.10(5) and 2.10(6) spores/ml gave a better expression of resistance. With 2.10(4) spores/ml, the two components latent period and spore production were not expressed on the resistant genotype BPL710.