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International Society for Infectious Diseases
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International Society for Infectious Diseases <http://www.isid.org>
Date: 12 Jul 2007
Source: North American Plant Protection Organization (NAPPO),
Phytosanitary Alert System (PAS) [edited] <http://www.pestalert.org/oprDetail.cfm?oprID=267>
Detection of Asian soybean rust (Phakopsora pachyrhizi)
in yam bean crops in Papantla, Veracruz, Mexico
In the middle of January 2007, the Plant Health General
Directorate received samples of yam bean (_Pachyrhizus erosus_)
crop foliage from the communities of Agua Dulce and Pajapan, in
Papantla township, in the state of Veracruz. These samples
showed signs and symptoms of Asian soybean rust (_Phakopsora
pachyrhizi_).
The samples were analysed and processed by technical personnel
of the National Center for Phytosanitary Reference Mycology
Laboratory, to determine the pathogen. To this end, it was
necessary to analyse the morphology of its reproductive
structure, as well as to conduct a molecular analysis. The
results of these analyses confirmed the presence of the disease
called Asian soybean rust.
Through the Plant Health Committee of Veracruz, the SENASICA
[Servicio Nacional de Sanidad, Inocuidad y Calidad
Agroalimentaria] did a follow-up of the detected outbreak,
taking immediate actions to prevent the spread of the disease to
other hosts by applying triazole and strobiruline fungicides.
Furthermore, given the importance of the disease, yam bean
growers carried out a phytosanitary survey as a culture measure
in the areas where the disease was more advanced, to minimize
the inoculation source for the next cycles of the crops.
[Byline: J. Trujillo Arriaga, <jtrujillo@senasica.sagarpa.gob.mx>]
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[The fungus _Phakopsora pachyrhizi_ was identified in Japan in
1902 as the cause of soybean rust. It can cause premature
defoliation, with yield losses of up to 70 percent reported in
farms in Asia. It is widespread in Asia and Africa, but data are
lacking concerning its establishment in Europe. The 1st
detection of _P. pachyrhizi_ in the New World was in Paraguay in
2001, and it was introduced into the USA in 2004. The 1st
detection in Mexico occurred in 2005, on soybean (_Glycine max_)
in Tamuin, State of San Luis Potosi, and in Altamira, State of
Tamaulipas.
New strains of _P. pachyrhizi_ with increased virulence are
emerging and weed species can serve as pathogen reservoirs. A
less-virulent related species (_P. meibomiae_) is found in South
America and also causes rust symptoms.
Yam bean (also called Jicama, Mexican potato) is a leguminous
vine native to the tropical Americas that can reach a length of
several meters. Roots can weigh up to 20 kg (44 lb) and are
usually eaten raw. Seeds are eaten cooked.
Maps
Mexico:
<http://www.mexico.us/map.htm>
Veracruz:
<http://www.travelamap.com/mexico/veracruz.htm>
Worldwide distribution of soybean rust up until December 2005:
<http://www.eppo.org/QUARANTINE/Alert_List/fungi/maps/PHAKPA_map.htm>
Pictures
Soybean rust symptoms on soybean:
<http://soybeanrust.unl.edu/soybean/siteImages/plantdate.gif>
and via <http://www.plantmanagementnetwork.org/search/image/search_action.asp?keyword=soybean+rust&type=all&imagetype=&B1=Submit>
Yam bean plant:
<http://pharm1.pharmazie.uni-greifswald.de/systematik/7_bilder/yamasaki/yamas150.jpg>
Yam bean tuber:
<http://www.sci.sdsu.edu/plants/econbot/vegpls/jpgs/Pachyrhizus_erosus.jpg>
Yam bean pod with seeds: click
HERE
Links
Information on soybean rust:
<http://www.aphis.usda.gov/plant_health/plant_pest_info/soybean_rust/background.shtml>
and
<http://www.eppo.org/QUARANTINE/Alert_List/fungi/PHAKPA.htm>
Diagnostic fact sheet:
<http://nt.ars-grin.gov/taxadescriptions/factsheets/index.cfm?thisapp=Phakopsorapachyrhizi>
Disease history and background:
<http://www.apsnet.org/online/feature/rust/>
_P. pachyrhizi_ taxonomy:
<http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=121037>
_P. meibomiae_ taxonomy:
<http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=102469>
SENASICA
<http://www.senasica.sagarpa.gob.mx/>.
- Mod.DHA]
[see also in the
archive:
2006
----
Soybean rust - Mexico (02) 20060525.1476 Soybean rust - Mexico:
1st report 20060219.0546] |
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