Potential threat of Ceratocystis lukuohia to kiwifruit

Authors: CASSOL, SABRINA - Universidade Federal De Vicosa; Keith, Lisa; PAL, CHANDAN - Zespri Group Limited; ALFENAS, ACELINO - Universidade Federal De Vicosa; ALFENAS, RAFAEL - Universidade Federal De Vicosa

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2024
Publication Date: 11/19/2024
Citation: Cassol, S.A., Keith, L.M., Pal, C., Alfenas, A.C., Alfenas, R.F. 2024. Potential threat of Ceratocystis lukuohia to kiwifruit. European Journal of Plant Pathology. https://doi.org/10.1007/s10658-024-02980-4.
DOI: https://doi.org/10.1007/s10658-024-02980-4

Interpretive Summary: Ceratocystis fimbriata sensu lato is a complex of fungal pathogens that cause disease on a wide variety of host plants, including wilt and death of kiwifruit plants in Brazil. Ceratocystis lukuohia and C. huliohia cause the phenomenon referred to as rapid ohia death (ROD) in Hawaii. A study was conducted to determine if the ROD pathogens could cause disease in kiwifruit vines and results showed that C. lukuohia is pathogenic on this host. This is the first time that C. lukuohia has been shown to infect plant species outside the Metrosideros genus, indicating that C. lukuohia is not host specific. Therefore, it is essential to prevent the introduction of C. lukuohia into kiwifruit-producing countries, especially those where native Metrosideros species coexist.

Technical Abstract: Ceratocystis species are responsible for causing ceratocystis wilt in forestry and agronomic crops across numerous countries. Some Ceratocystis isolates are host-specific, while others are multihost. In Brazil, ceratocystis wilt stands out as the most severe disease affecting kiwifruit (Actinidia spp.), posing a threat to other kiwifruit-producing countries where Ceratocystis species have not yet been reported infecting kiwifruit plants. Where Ceratocystis isolates from different hosts and countries can infect kiwifruit, it is important to implement biosecurity measures that prevent the introduction of these isolates into kiwifruit-producing areas. In the present work, we assessed whether C. lukuohia and C. huliohia, isolated from diseased 'ohi'a trees (Metrosideros polymorpha) in Hawaii, can cause ceratocystis wilt in kiwifruit cultivars. Inoculations of both species in rooted cuttings of Monty and Zesy002 cultivars showed that C. lukuohia can infect and cause wilt and death in both kiwifruit cultivars, while C. huliohia was not able to infect either kiwifruit cultivar evaluated. The finding that C. lukuohia can infect plant species outside the Metrosideros genus indicates that it is not a host-specific Ceratocystis species, underscoring the importance of assessing the pathogenicity of this fungal species to other agricultural and forestry crops in Hawaii and the Pacific Basin. This is the first work demonstrating that C. lukuohia is pathogenic and lethal to kiwifruit plants. Therefore, it is essential to prevent the introduction of this pathogen into kiwifruit-producing countries, especially those where native Metrosideros species coexist.