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Susceptibility of native New Zealand Myrtaceae to the South African strain of Austropuccinia psidii : A biosecurity threat
Author(s) -
Soewarto Julia,
Somchit Chanatda,
Plessis Esna,
Barnes Irene,
Granados Ginna M.,
Wingfield Michael J.,
Shuey Louise,
Bartlett Michael,
Fraser Stuart,
Scott Peter,
Miller Elizabeth,
Waipara Nick,
Sutherland Roanne,
Ganley Beccy
Publication year - 2021
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.13321
Subject(s) - myrtaceae , biology , melaleuca , botany , syzygium
Austropuccinia psidii , cause of myrtle rust, has spread globally where Myrtaceae occur. Multiple strains of A . psidii have been identified, including a unique strain found only in South Africa. The South African strain is a biosecurity concern for species of Myrtaceae worldwide. This is because preliminary testing of South African Myrtaceae suggests it could have a wide host range, and thus has the potential to be invasive. In this study, we assessed the ability of the South African strain to infect other species of Myrtaceae by testing the susceptibility of New Zealand provenance Myrtaceae. Seedlings of four native New Zealand Myrtaceae species ( Metrosideros excelsa , Leptospermum scoparium , Kunzea robusta , and Kunzea linearis ) were artificially inoculated in South Africa with a single‐uredinium isolate of the South African strain. Fourteen days after inoculation, uredinia, and in many cases telia, had developed on the young leaves and stems of all four host species, which led to shoot tip dieback in the more severe cases. When comparisons were made between the species, K . robusta was the least susceptible to the South African strain of A . psidii , while L . scoparium and M . excelsa were the most susceptible. While only a limited number of seed families were tested, only a small proportion of the seedlings showed resistance to infection by the South African strain. This preliminary testing highlights the potential invasive risk the South African strain poses to global Myrtaceae communities, including New Zealand Myrtaceae.