Bacterial soft rot, caused by the pathogen Pectobacterium carotovorum subsp. carotovorum, seriously impacts the production of calla lilies Zantedeschia spp. Methyl jasmonate (MeJA) is a plant hormone involved in regulating plant-pathogen interactions and responses to environmental stress through modulating gene expressions. A leaf spray of Z. aethiopica with MeJA at 1, 10, and 45 mM significantly elicited tolerance of the leaf disc against P. carotovorum. The infection rate of leaf discs with 1 and 45 mM of MeJA decreased to 55.6%, and that with 10 mM of MeJA declined to 5.6%. Although foliar application of MeJA at 1 mM is less efficient than that of 10 mM, the maceration symptom of calla lily was negligible compared to the control. Therefore, foliar application of MeJA at 1 mM is cost-effective for application in field cultivation of calla lily against soft rot.
