Bacterial soft rot caused by Erwinia carotovora subsp. carotovora is a major disease in Zantedeschia spp. Chemicals or modified cultivation methods only provide partial control of this disease. So highly resistant cultivars are needed to produce high quality calla flowers. Experiments were conducted to screen for Erwinia resistance in Zantedeschia spp. by a leaf disk test. To determine variation for aggressiveness, 20 Erwinia isolates collected from sites at Jeonju, Pyeongchang, and Suwon were inoculated onto five Zantedeschia cultivars: including 'Wedding March' as a resistant genotype, 'Little Suzy' as a moderately resistant genotype, and 'Chianti' as a susceptible genotype. Ecc NHRI-3 and Ecc NHRI-6 were the most virulent isolates among the 20 isolates of Erwinia carotovora subsp. carotovora tested. Within 25 Zantedeschia genotypes, including Z. rehmannii and Z. albomaculata, variation of Erwinia resistance ranged from almost completely resistant to extremely susceptible. 'Wedding March' was the most resistant, while 'Galaxy' was the most susceptible.