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MYRTLE RUST
Austropuccina (formerly Puccina) psidii


Myrtle rust, also called guava rust or ʻōhiʻa rust in Hawaiʻi, is a plant pathogen that has spread from its origin in Latin America to Hawaiʻi, the Pacific, Australia, and New Zealand in the past few years. The fungus has a broad host range, attacking most trees in the myrtle family (Myrtaceae), including guava, Eucalyptus, Eugenia, Melaleuca (paperbark), and Metrosideros (ʻōhiʻa and pohutukawa), and Syzygium (mountain apple and rose apple in Hawaiʻi). Different strains of the fungus are virulent on different tree species. In severe cases the host tree suffers repeat defoliations and is eventually killed. Efforts to contain the rust have so far not been successful.


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Austropuccinia rust on ʻōhiʻa, Metrosideros polymorpha.

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Austropuccinia rust on ʻōhiʻa, Metrosideros polymorpha.

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Austropuccinia rust on ʻōhiʻa, Metrosideros polymorpha.

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Austropuccinia rust on ʻōhiʻa, Metrosideros polymorpha.

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Rust on rose apple.

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Rust damage on Eugenia koolauensis.

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Rust on Eugenia koolauensis.

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Rust on Eugenia koolauensis.

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Rust damage on Eugenia koolauensis.

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Myrtle rust damage on Eugenia koolauensis.

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Austropuccinia (formerly Puccinia) psidii.

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Austropuccinia on downy rose myrtle Rhodomyrtus tomentosa.

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Austropuccinia on downy rosemyrtle Rhodomyrtus tomentosa.

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Austropuccinia rust on brush cherry, Eugenia paniculatum.

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Austropuccinia rust defoliation of Eugenia paniculata.

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Rust on jaboticaba.

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Rust on paperbark, Melaleuca quinquenervia.

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Rust on paperbark, Melaleuca quinquenervia.



PHOTO GALLERY

Gallery of photos of myrtle rust in Hawaii:
https://www.flickr.com/search/?user_id=53814102%40N04&sort=date-taken-desc&text=Puccinia&view_all=1


June 2014

Costa da Silva, A; PM Teixeira de Andrade, A Couto Alfenas, R Neves Graca, P Cannon, R Hauff, D Cristiano Ferreira, and S Mori. 2014.  Virulence and Impact of Brazilian Strains of Puccinia psidii on Hawaiian Ohia (Metrosideros polymorpha). Pacific Science 68(1):47-56. doi: http://dx.doi.org/10.2984/68.1.4

January 2013

Hauff, R. 2012. A baseline analysis of the distribution, host-range, and severity of the rust Puccina psidii in the Hawaiian Islands, 2005 – 2010 . Technical Report HCSU-031. USGS, Honolulu, HI.

July 2010

Molecular genetic studies highlight potential threat of guava rust (aka ohia rust, in Hawaii) to Myrtaceae.” Summary of a presentation at the University of Hawaii, July 13, 2010 by Rodrigo Neves Graça, of the Universidade de Viçosa in Brazil.

Puccinia rust was identified on myrtle plantings in San Diego, California in 2005.

Loope, L. 2010. A summary of information on the rust Puccinia psidii Winter (guava rust) with emphasis on means to prevent introduction of additional strains to Hawaii: U.S. Geological Survey Open-File Report2010-1082, 31 p.http://pubs.usgs.gov/of/2010/1082/

May 2008, Rust Survey

A survey of Puccinia rust on ohia and rose apple

Janice Uchida, Chris Kadooka, and Rob Anderson at CTAHR, Rob Hauff at DOFAW, and Anne Marie LaRosa at the USDA Forest Service IPIF are conducting a survey to obtain more information on the extent and severity of Puccinia rust infections statewide on ohia, rose apple, and other trees. While the disease spread statewide quickly, it is still unevenly distributed, especially on ohia. To help people identify the disease and report in a standard way, the authors have published a disease index for the rust on rose apple and on ohia with color photographs illustrating symptoms of the disease with varying degrees of severity on each species. A field survey form is attached to each index, and anyone who observes the rust in the field is invited to compare the severity of the infection with the photos in the index, fill out a survey form recording the severity of the infection and the species and location, and return the results to Dr. Uchida. If you are unsure of whether a disease is the Puccinia rust, the index lists scientists on Kauai, Oahu, Maui, and the Big Island who can confirm diagnosis. The information will be used to compile a statewide profile of the extent and hosts of the disease. Printed copies of the two disease indices are available at Cooperative Extension Service offices statewide. Completed surveys should be sent to: Dr. Janice Uchida, Dept. of Plant and Environmental Protection Services, CTAHR, University of Hawaii, St. John Hall 304, 3190 Maile Way, Honolulu, HI 96822

December 2007, Rust update

The State of Hawaii Department of Agriculture has issued an updated Pest Advisory on the rust disease on ohia.

November 2006, Rust database

A database of worldwide hosts of Puccinia rust, including new records from Hawaii. The database, by Rob Anderson of the USGS BRD PIERC, is available as an MS Excel spreadsheet.

A common algal leaf spot is similar in appearance to the Puccinia rust.

A common algal leaf spot is similar in appearance to the Puccinia rust. The algal leaf spots are on the upper surfaces of the leaves only and the colony has a green border with red spores in the center. The algae is presumably Cephaleuros virescens.

Red algae ID sheet  Algal leafspot on guava

Rust on native and introduced plant species

The rust has been observed defoliating the native species Eugenia koolauensis in Kahuku, Oahu, infecting downy rosemyrtle, Rhodomyrtus tomentosa, on Kauai, and infecting brush cherry, Eugenia paniculata, and jaboticaba, Myrciaria cauliflora, on the Big Island.

February 2006, Rust on rose apple

The rust has caused severe dieback on rose apple, Syzygium jambos, on Oahu.

November 2005, Rust update

Rust has been found on all major islands. Infections have occurred on rose apple and paper bark in the Hilo area.

July 2005, Rust update

Similar-looking rusts have been reported on Eugenia koolauensis and E. reinwardtiana, and common guava, Psidium guajava, all an Oahu. The Hawaii Department of Agriculture has tentatively identified the rust as Puccinia psidii, a serious pest of Eucalyptus and other genera in the family Myrtaceae. A new pest advisory has been released by the state Department of Agriculture and growers are asked to refrain from transporting any ohia, guava, eucalyptus, or other plants in the family Myrtaceae between islands. Growers finding rust symptoms on ohia, guava, eucalyptus, rose apple, or Eugenia, ar asked to call the state Department of Agriculture at 808-973-9546. For more information, see the Florida pest alert on Puccinia psidii and an article on the danger of Puccina psidii reaching Australia, the home of Eucalyptus.

May 2005, Rust update

The rust has been found on natural populations of ohia on Oahu. A similar-appearing rust has also been found on rose apple, Syzygium jambos.

A new rust occuring on ohia, Metrosideros polymorpha

An unidentified rust has been found on nursery seedlings of ohia, Metrosideros polymorpha. This could be a new disease to Hawaii's most common forest tree. If you are a grower and have plants showing these symptoms, you are encouraged to bring in samples to any UH Cooperative Extension Service office or the Komohana Agriculture Complex in Hilo for submission to the Agricultural Diagnostics Service Center (ADSC).

More information on Puccinia rust at the Hawaii Ecosystems at Risk website.


REFERENCES on Austropuccinia Rust

Scientific articles on Puccinia rust in Hawaii and elsewhere, many available on-line.

Beenken, L. 2017. Austropuccinia: a new genus name for the myrtle rust Puccinia psidii placed within the redefined family Sphaerophragmiaceae (Pucciniales). Phytotaxa 297 (1): 53-61. https://doi.org/10.11646/phytotaxa.297.1.5

Burnett, K., S. D’Evelyn, L. Loope, and C. Wada. 2012. An economic approach to assessing import policies designed to prevent the arrival of invasive species: the case of Puccinia psidii in Hawai‘i, Environmental Science and Policy 19-20: 158-168. doi:10.1016/j.envsci.2012.03.006

Coutinho, TA, MJ Wingfield, AC Alfenas, and PW Crous. 1998. Eucalyptus rust: a disease with the potential for serious international implications. (acrobat reader 1.3 MB) Plant Disease 82: 19-825.

Glen, M, AC Alfenas, EAV Zauza, MJ Wingfield, and C Mohammed. 2007. Puccinia psidii: a threat to the Australian environment and economy – a review. Australasian Plant Pathology 36(1) 1–16. Abstract only. “The pathogen has recently expanded its geographical range to Hawaii, increasing concerns about the potential for an incursion in Australia. This paper reviews the taxonomy, biology, impact and options for control of P. psidii. It also discusses the probable impact if an incursion were to occur in Australia and the preparations that must be made to mitigate adverse consequences.”

Grgurinovic, CA, D Walsh, and F Macbeth. 2006. Eucalyptus rust caused by Puccinia psidii and the threat it poses to Australia. EPPO Bulletin 36: 486–489. “Puccinia psidii, which causes the disease Eucalyptus rust, poses a threat to biodiversity in Australia and the Eucalyptus forest industry worldwide. It is native to South America and Central America and has spread to North America (Mexico, USA – Florida). In mid-2005, the rust was reported in Hawaii, USA, which means it is now present in the Pacific region.”

Haines, R, J Simpson, and M Cole. November 2006. Developing an Australian Guava Rust Strategy acrobat reader "… ACIAR has supported some pioneering work on guava rust. This seminar will present the rationale for and scope of this work, and then go on to discuss the risk that guava rust poses for Australia, and the interest of State and federal biosecurity and agricultural authorities in participation in a regional approach to the threat.”

Hauff, R. 2012. A baseline analysis of the distribution, host-range, and severity of the rust Puccina psidii in the Hawaiian Islands, 2005 – 2010. acrobat icon Technical Report HCSU-031. USGS, Honolulu, HI.

Kadooka, C. 2010. Current molecular characterization and disease management results for Puccinia psidii, the ohia rust. acrobat icon Pp. 48-54 in: Cram, M., ed. Proceedings of the 7th meeting of IUFRO Working Party 7.03.04 Diseases and Insects in Forest Nurseries. July 13 – 17, 2009, Hilo, Hawaii. USDA Forest Service Southern Region Forest Health Protection Report 10-01-01.

Langrell, SRH, M Glen, AC Alfenas. 2008. Molecular diagnosis of Puccinia psidii (guava rust) – a quarantine threat to Australian eucalypt and Myrtaceae biodiversity. Plant Pathology 57 (4): 687-701. DOI: 10.1111/j.1365-3059.2008.01844.x

La Rosa, AM and R Hauff. 2006. Incidence and Evaluation of a New Rust Disease on Myrtaceae in Hawaii: Puccinia psidii Winter, Guava Rust. (acrobat reader poster) USDA Forest Service, Institute of Pacific Islands Forestry and Hawaii State Department of Land and Natural Resources, Division of Forestry and Wildlife.

Loope, L. 2010. A summary of information on the rust Puccinia psidii Winter (guava rust) with emphasis on means to prevent introduction of additional strains to Hawaii: U.S. Geological Survey Open-File Report 2010-1082, 31 p. http://pubs.usgs.gov/of/2010/1082/

Loope, LLoyd, and AM LaRosa. 2008. An analysis of the risk of introduction of additional strains of the rust Puccinia psidii Winter (`ohi`a rust) to Hawai`i. acrobat reader US Geological Survey Open File Report 2008-1008, Reston, Virginia.

Loope, L., and A. LaRosa. 2010. Protecting Hawaii’s forests from harm: an argument for strong measures to prevent arrival of pests of Hawaii’s Myrtle family. acrobat icon Pp. 2-15 in: Cram, M., ed. Proceedings of the 7th meeting of IUFRO Working Party 7.03.04 Diseases and Insects in Forest Nurseries. July 13 – 17, 2009, Hilo, Hawaii. USDA Forest Service Southern Region Forest Health Protection Report 10-01-01.

Simpson, JA, K Thomas and CA Grgurinovic. 2006. Uredinales species pathogenic on species of Myrtaceae. Abstract only Australasian Plant Pathology 35: 546-562.
”Guava rust, Puccinia psidii, is now known to occur on species in both subfamilies of Myrtaceae, including one of two tribes of the subfamily Psiloxyloideae and seven of the 15 tribes of subfamily Myrtoideae, a total of 20 genera and 71 species. Susceptibility to Puccinia psidii seems to be low among species of Myrtaceae from the Americas but more common among taxa from Asia, Australia and the Pacific.”

Uchida, J, S Zhong, and E Killgore. 2006. First Report of a Rust Disease on Ohia Caused by Puccinia psidii in Hawaii. Plant Disease 90: 524.

Zhong S, B Yang, and AC Alfenas. 2008. Development of microsatellite markers for the guava rust fungus, Puccinia psidii. Molecular Ecology Resources 8: 348–350. doi: 10.1111/j.1471-8286.2007.01952.x



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