Phytophthora cinnamomi
Phytophthora cinnamomi | |
---|---|
A: seven-day-old colony on PARP medium; B: sporangia; C: gametangia; D: oospore. | |
Scientific classification | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | SAR |
Clade: | Stramenopiles |
Phylum: | Oomycota |
Order: | Peronosporales |
Family: | Peronosporaceae |
Genus: | Phytophthora |
Species: | P. cinnamomi
|
Binomial name | |
Phytophthora cinnamomi | |
Varieties | |
Phytophthora cinnamomi, also known as cinnamon fungus, is a soil-borne
Once infected soil or water is introduced, the organism can spread rapidly throughout an environment. An infestation can lead to the illness, death, and possible eradication of vulnerable plants, as well as habitat reduction for animals. An outbreak can be challenging to recognize and can inflict irreversible harm to ecosystems.[1]
The plant pathogen is one of the world's most invasive species and is present in over 70 countries around the world.
Distribution and hosts
Phytophythora cinnamomi is distributed worldwide and can infect a diverse range of hosts, including
It affects a range of economic plants, including food crops such as
Reproduction
Phytophthora cinnamomi is a
Life cycle
Phytophthora cinnamomi lives in the soil and in plant tissues and can spread in water.
Transmission
Although P. cinnamomi was first identified in tropical and subtropical countries, but can survive and develop in cooler climates as well.[10] It spreads as zoospores and/or chlamydospores in soil and water under favourable conditions such as warm temperatures and high soil moisture.
Methods of transmission include local invasion via contact between the roots of infected and susceptible plants, downslope movement in surface or subsurface water such as rivers or irrigation water, zoospore dispersal over long distances via wind-blown soil and debris, and transport of infected plant matter and soil, for example via particles stuck to footwear, vehicles or equipment.[4][5][11] Native and feral animals have been known to transport the disease, including through the digestive tract of feral pigs.[4] However human activities such as timber harvesting, mining, bush walking, and road construction are also major methods of dispersal.[10]
Environmental impacts
When Phytophthora dieback spreads to native plant communities, it kills many susceptible plants, resulting in a permanent decline in the biodiversity and a disruption of ecosystem processes.[1] It can also change the composition of the forest or native plant community by increasing the number of resistant plants and reducing the number of susceptible plant species. Native animals that rely on susceptible plants for survival are reduced in numbers or are eliminated from sites infested by Phytophthora dieback.[12]
Australia
In Australia, where it is known as phytophthora dieback, dieback, jarrah dieback or cinnamon fungus, Phytophthora cinnamomi can infect thousands of native plants, causing damage to forests and removing habitats for wildlife.[12][13][14] Several native plants are at risk of extinction due to the effects of the disease.[12]
Phytophthora cinnamomi's impact is greatest in Western Australia, Victoria, Tasmania and South Australia, while the Northern Territory remains unaffected due to the unfavourability of the environment.[12]
Of particular concern is the infection and dieback of large areas of forest and heathland which support
U.S. and Mexico
Damage to forests suspected to be caused by Phytophthora cinnamomi was first recorded in the
Phytophthora cinnamomi is also a problem in the
Commercial effects
Phytophthora cinnamomi is the leading cause of damage to avocado trees, and is commonly known as "root rot" amongst avocado farmers. Since the 1940s various breeds of root rot-resistant avocados have been developed to minimize tree damage. Damaged trees generally die or become unproductive within three to five years. A 1960 study of the Fallbrook, California, area correlated higher levels of avocado root rot to soils with poorer drainage and greater clay content.[17]
Control
No treatment has been found to eradicate P. cinnamomi, although an integrated approach can control the spread and impact of the disease.
Gardening practices to restrict spread include restricting soil or water movement from infected areas by using clean bins and equipment, installing watertight drains to prevent surface run off, and working last in diseased areas after harvesting healthy areas first.[18]
Planting in raised beds promotes rapid drainage and reduces prolonged contact of plant roots with water, making the soil environment less hospitable to P. cinnamomi.[6] For specific plants such as young avocado plants, soil solarisation by using clear polythene sheets laid on the soil surface to trap radiant heat from the sun can reduce spread, and an integrated approach is generally taken to control disease on avocado.[4]
Chemical means of control include fumigation and the use of phosphonate fungistats.[19] Fumigation prior to planting may be effective on some life stages of P. cinnamomi, but does not eliminate chlamydospores as they are present deeper in the soil where fumigation may not reach.[6] However, fumigation can potentially worsen disease by reducing the population of competing soil microorganisms, and P. cinnamomi is often able to re-invade fumigated soil.
Phosphonate fungistats can improve the ability of a tree to tolerate, resist, or recover from infection. Phosphite administered through direct foliage sprays, aerial application by aircraft or direct injection has been used to limit the disease with some success and has been recognized as a major strategy for disease prevention.[18]
Commonly
See also
- Chlorosis
- Forest pathology
References
- ^ a b c "Phytophthora dieback". Australian Government - Department of Climate Change, Energy, the Environment and Water. 3 October 2021. Retrieved 11 April 2023.
- ^ "100 of the World's Worst Invasive Alien Species". Invasive Species Specialist Group. Retrieved 6 June 2019.
- .
- ^ a b c d "Data Sheets on Quarantine Pests: Phytophthora cinnamomi" (PDF). EPPO and CABI.[permanent dead link]
- ^ a b "Phytophthora cinnamomi (Phytophthora dieback)". CABI.
- ^ a b c Reuter, Courtney. "Phytophthora cinnamomi Rands". NCSU. Archived from the original on 2020-05-13. Retrieved 2017-12-12.
- PMID 18945050.
- .
- ISBN 9780646493046. Archived from the original(PDF) on 2014-03-06. Retrieved 2013-09-17.
- ^ ISSN 2164-7232.
- doi:10.1071/bt07159.
- ^ a b c d "Arrive Clean, Leave Clean" (PDF). environment.gov.au. April 12, 2023. p. 4. Retrieved April 12, 2023.
- ^ Cinnamon Fungus. Parks Victoria. parkweb.vic.gov.au
- ^ Groves, E.; Hollick, P.; Hardy, G.; McComb, J. "WA list of susceptible plants" (PDF). Murdoch University.
- .
- ^ Swiecki, T. J.; Bernhardt, E. A. (2003). "Diseases threaten the survival of Ione manzanita (Arctostaphylos myrtifolia)". Phytosphere Research.
- ^ Burns, R. M.; Miner, J. H.; Gustafson, C. D.; Zentmyer, G. A.; Thorn, W. A. (1960). "Correlation of soil series and avocado root rot damage in the Fallbrook area" (PDF). Yearbook. Vol. 44. California Avocado Society. pp. 110–113.
- ^ ISSN 1444-9862.
- ^ "Avocado Phytophthora Root Rot". UC IPM. Archived from the original on 2018-01-29. Retrieved 2017-12-12.
- S2CID 95723306.
External links
- "Phytophthora root rot — fact sheet". Botanic Gardens Trust. Archived from the original on 7 March 2005.
- "Centre for Phytophthora Science & Management". Murdoch University.
- "Phytophthora is killing our plants!" (PDF). Department of Environment, Water and Natural Resources, South Australia.
- "Dieback Web Portal". Archived from the original on 2020-10-21. Retrieved 2009-06-24.
- "Dieback Working Group".
- "Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi". Australian Government Department of the Environment, Water, Heritage and the Arts. 2009.
- Hansen, E. (2003). "Phytophthora in North American forests" (PDF). Sudden Oak Death Online Symposium.
- Wills, R.T. (November 1995). "Plant Diseases in the south-west of Western Australia – a summary".
- Zentmyer, G.A. (1980). Phytophthora cinnamomi and the Diseases it Causes. Monograph (American Phytopathological Society). Vol. 10. APS Press. ISBN 0890540306.
- fact sheet of the Global Invasive Species database
- "Managing dieback". Department of Environment and Conservation Western Australia. 2009. Archived from the original on 2009-06-12.
- Groves, E.; Hardy, G.; McComb, J. (2003). "List of native garden plants resistant to Dieback (Phytophthora cinnamomi)" (PDF). Murdoch University. Retrieved 2009-10-07.