A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Sun 23 Sep 2012
Source: Proplanta [in German, trans. & summ. Mod.DHA, edited] <http://www.proplanta.de/Agrar-Nachrichten/Pflanze/Gelbrost-Rueckkehr-Weizenkrankheit_article1348381412.html>
Stripe rust: return of a wheat disease
After 10 years of absence, stripe rust has appeared in 2012 in all wheat and triticale-producing regions of Switzerland north of the Alps.
The investigations of Agroscope show that the infection was caused by a strain with virulences [see comment below] not previously reported in Switzerland. The disease affected certain wheat varieties, as well as triticale to a lesser degree. Disease severity also depended on the region. The results will form the basis for the adjustment of the list of recommended varieties.
Agroscope studied 3 stripe rust strains, from France, Belgium, and Switzerland, which are identical and show virulences new to Switzerland. In 2009, a strain with an unknown virulence was reported in Switzerland (ProMED-mail post 20091228.4366). The 2012 strain contains the virulence identified in 2009 as well as additional virulences.
Stripe rust occurs only rarely in Switzerland and current wheat and triticale varieties generally have good resistance. For an epidemic, both favourable weather conditions and the presence of a pathogen strain able to overcome existing host resistances are needed, and this is what happened in 2012. Breeding efforts are required again to develop new resistant crop cultivars.
[Stripe rust (also called yellow rust) of cereals is caused by the fungus _Puccinia striiformis_ var. _striiformis_. The disease affects wheat, some barley varieties, triticale, and a number of wild grasses.
It causes yellow leaf stripes and stunting of plants with yield losses of 40 to 100 percent in wheat.
Spores are wind dispersed in several cycles during the cropping season. Between seasons, the fungus survives on living host plants generating a "green bridge". Disease management includes the use of resistant varieties, fungicide applications, and control of volunteer crops.
New stripe rust strains with increased virulence are emerging worldwide. These include strains that show additional fungicide resistances and/or new "virulences" (ability to break down disease resistance conferred by specific host genes). 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.
Triticale (wheat-rye hybrids) affecting strains of stripe rust have also been reported, for example, from Australia (see links below) and Denmark (ProMED-mail posts 20120426.1114329). It is not clear whether the triticale virulence reported above is thought to be the same as the Danish one.
A related pathogen, _P. hordei_ (previously _P. striiformis_ f.sp.
_hordei_), affects only barley.
<http://www.idsia.ch/wea2003/map_switzerland.gif> and <http://healthmap.org/r/1AFv> Swiss cantons:
Stripe rust symptoms on wheat:
(leaf) and via
Barley with stripe rust:
Ryegrass with stripe rust:
Information on wheat stripe rust:
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>, and <http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/158964/stripe-rust-in-wheat.pdf>
Stripe rust management:
<http://www.grdc.com.au/uploads/documents/striperustmgt.pdf> and <http://www.ipm.ucdavis.edu/PMG/r730100511.html>
Examples of stripe rust triticale strains:
_P. striiformis_ taxonomy:
Definition of strains, pathotypes, and races of rusts:
<http://www.agroscope.admin.ch/aktuell/index.html?lang=en>. - Mod.DHA]
Stem & stripe rusts, wheat: double resistance breeding
Stripe rust, triticale - Denmark: new strain susp 20120426.1114329 Leaf & stripe rusts, wheat - UK: new strains 20120208.1036727 Stripe rust, wheat - India: update 20120122.1017973
Barley diseases - India: (JK) survey 20111201.3497 Stripe rust, barley - Australia: (NS) 20111103.3270 Stripe rust & foot rot, wheat - USA, UK 20110713.2109 Stripe rust, wheat - India, UK: spread 20110404.1042 Stripe rust, wheat - UK: (England), Claire strain 20110304.0705 Fungal diseases, cereals - Australia: (eastern, south) alert
Stripe rust, wheat - India: (PB) 20110211.0469
Stripe rust, wheat - Lebanon 20101121.4214 Stripe rust, wheat - Turkey, Syria 20101021.3815 Stripe rust, wheat - Ethiopia 20100922.3420 Fungal diseases, cereals - Australia: alert 20100825.2989 Stripe rust, soft wheat - Syria (east) 20100609.1930 Stripe rust, wheat - Africa, Asia: new strain 20100531.1803 Stripe rust, wheat - USA: (AR) new strains, alert 20100510.1522 Stripe rust & downy mildew, cereals - USA: (TX) 20100504.1443 Fungal diseases, maize, wheat - USA 20100331.1017 Stripe rust, wheat - India, UK: alert 20100121.0234
Stripe rust, wheat - Switzerland 20091228.4366 Stripe rust, wheat - UK (03): alert 20091218.4274 Cereal rusts - Australia: (WA) alert 20090820.2948 Stripe rust, wheat - Australia 20090813.2884 Stripe rust, wheat - Canada: (AB) alert 20090724.2614 Fungal diseases, cereal crops - China, Ireland 20090528.1983 Stripe rust, wheat - UK (02): new strain 20090514.1806 Rust diseases, wheat - UK, Pakistan 20090424.1543 Stripe rust, wheat - UK 20090417.1452 Stripe rust, wheat - India: new strain 20090329.1216 Wheat rusts - Kenya, India, Australia 20090312.1019 Rust diseases, wheat, mustard - India: (JK) 20090305.0897 Stripe rust, wheat - China 20090208.0579 and older items in the archives]