Tests for determining resistance to Fusarium oxysporum f.sp. lilii in different developmental stages of Lilium were developed. Under standardized conditions, commercial bulbs, yearling bulbs, scale bulblets, and scales of 16 Asiatic lily cultivars were tested for Fusarium resistance. Disease ratings were analyzed statistically using a threshold model for ordered categorical data. For each cultivar in each stage the resistance level was calculated as the disease severity score (DSS). Disease severity score values of cultivars in the four stages were reproducible between experiments, although some variation in cultivars was found. This variation may be attributed to the origin of plant material. Disease severity score values among cultivars in each developmental stage were correlated with the average DSS over all four stages, although some specific cultivar-stage deviations were found. The scale test is recommended for early selection while the scale bulblet test is recommended as a final check.