A ProMED-mail post
http://www.promedmail.org
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International Society for Infectious Diseases
http://www.isid.org

Date: Fri 5 Aug 2022
Source: Grain Central [summ. Mod.DHA, edited]
https://www.graincentral.com/cropping/nsw-qld-conditions-create-early-stripe-rust-epidemic/


Stripe rust reports from the northern grain growing region have been increasing. Ongoing rain and the survival of a significant green bridge over summer have generated conducive conditions. Across both New South Wales and Queensland, growers have been noticing high stripe rust occurrences in emerging crops, even cases of low levels in resistant to moderately resistant varieties.

Infections wouldn't usually be observed this early in the season, but the green bridge has supported earlier inoculum development, resulting in significantly more seedling infections in 2022. Growers should consider an early fungicide application in later sown crops. All varieties are susceptible at an early stage, but once resistant varieties are established, their resistance genes come into effect.

Globally, it is estimated that over 5 million tonnes of wheat are lost each year to stripe rust alone.

--
Communicated by:
ProMED

[Stripe rust (also called yellow rust) of cereals is caused by the fungus _Puccinia striiformis_. The disease affects wheat (_Triticum aestivum_), durum wheat (_T. turgidum_), some barley varieties, triticale (wheat/rye hybrids), and a number of wild grasses. It causes yellow stripes on leaves, which leads to loss of photosynthetic ability and plant vigour, as well as stunting of plants. Yield losses of 40-100% have been reported in wheat.

Spores are wind dispersed in several cycles during the cropping season. Grasses and volunteer crop plants may generate a "green bridge" providing inoculum for the next crop cycle. Disease monitoring is important so that timely action can be taken to limit the spread of the pathogen as well as build-up of inoculum. Disease management may include the use of resistant varieties, fungicide applications, and control of pathogen reservoirs. Monitoring and resistance breeding programmes have been established in different regions for early detection of new rust strains and to attempt to stay ahead of pathogen evolution.

While stem rust (_P. graminis_) poses a huge potential threat to world wheat production, stripe rust is currently causing the most damage to wheat crops on a global scale. New strains of both rusts with increased virulence and additional fungicide resistances have been reported in recent years from wheat-growing areas worldwide, including Australia (e.g. ProMED post 20180614.5855829). Climate warming allowing survival of wheat rusts on green bridges into higher latitudes is another example of pathogens extending their range due to climate change (e.g. ProMED posts 20141024.2895414, 20120809.1235745, 20090914.3230, and 20110718.2172). Projects for double-resistance breeding to manage both stripe and stem rusts simultaneously are in progress (see ProMED post 20120831.1274190).

Maps
Australia (with states):
https://www.nationsonline.org/maps/australia-political-map.jpg and
https://promedmail.org/promed-post?place=8704948,186

Pictures
Stripe rust symptoms on wheat:
https://www.realagriculture.com/wp-content/uploads/2014/07/stripe-rust-3-signature-small2.jpeg,
http://www.plantmanagementnetwork.org/pub/php/brief/2005/stripe/image/wheat3.jpg, and
https://www.agric.wa.gov.au/sites/gateway/files/styles/original/public/Stripe%20rust%20infected%20glume.JPG
Stripe rust on barley:
http://www.planthealthaustralia.com.au/wp-content/uploads/2013/04/Barley-stripe-rust-1.jpg,
https://extensionaus.com.au/FieldCropDiseasesVic/wp-content/uploads/sites/25/2017/03/Fig-2.-Barley-stripe-rust-.jpg, and
https://pnwhandbooks.org/sites/pnwhandbooks/files/plant/images/barley-hordeum-vulgare-stripe-rust/225.jpg
Ryegrass with stripe rust:
http://www.science.oregonstate.edu/bpp/Plant_Clinic/images/ryegrass_stripe%20rust.jpg and
http://plant-pest-advisory.rutgers.edu/wp-content/uploads/2013/09/photo-15-e1378922274640.jpg

Links
Information on stripe rust:
https://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=45876,
https://www.ars.usda.gov/midwest-area/stpaul/cereal-disease-lab/docs/cereal-rusts/wheat-stripe-rust/,
https://www.agric.wa.gov.au/mycrop/diagnosing-stripe-rust-wheat,
http://www.planthealthaustralia.com.au/pests/barley-stripe-rust/,
http://www.ipm.ucdavis.edu/PMG/r730100511.html, and
http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/158964/stripe-rust-in-wheat.pdf
_P. striiformis_ life cycle:
https://www.nature.com/articles/ncomms3673/figures/1
Stripe rust global tracking, current race analysis, and distribution:
http://wheatrust.org/yellow-rust-tools-maps-and-charts/ and
http://rusttracker.cimmyt.org/?page_id=9
Stripe rust reviews:
https://doi.org/10.3389/fpls.2017.01057 and
https://globalrust.org/sites/default/files/posters/solh_2012.pdf
_P. striiformis_ taxonomy, and synonyms:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=227064 and
http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=227064
Wheat rusts overview, including epidemiology and spore types:
http://www.fao.org/3/y4011e/y4011e0g.htm
Global Rust Initiative:
https://bgri.cornell.edu/
- Mod.DHA

ProMED map:
Australia: https://promedmail.org/promed-post?place=8704948,186]

See Also

Stripe rust, cereal crops - Tunisia: (NB) 20220429.8702923
Stripe & leaf rusts, wheat - Pakistan: (PB) 20220210.8701378
2021
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Stripe, stem & leaf rusts, wheat - Ethiopia 20210212.8186216
Stripe rust, wheat - India: (HR) 20210120.8121602
2020
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Stripe rust, wheat - China 20200528.7391929
Stripe rust, wheat - UK: new strain susp. 20200410.7206768
Stripe rust & head blight, wheat - China 20200318.7104946
Stripe rust & karnal bunt, wheat - India: (HR) 20200204.6950281
2019
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Stripe rust, wheat - China: alert 20191219.6849959
Stripe rust, wheat - India: (JK) 20190415.6422450
Stripe rust, wheat - Pakistan, India 20190328.6390313
2018
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Stripe rust, wheat - Australia: (VI) new strain 20180614.5855829
Stripe rust, wheat - India: (PB) alert 20180301.5659889
2011
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Stripe rust, barley - Australia: (NS) 20111103.3270
Fungal diseases, cereals - Australia: (eastern, south) alert 20110218.0531
and additional items on stripe rust in the archives

Website: http://www.isid.org

Published: August 10, 2022