Rome, Italy
April 12, 2007
A new and virulent fungus that
attacks a wide range of wheat varieties has spread from East
Africa to Yemen on the Arabian Peninsula,
FAO reported today.
The wheat stem rust (Puccinia graminis), also known as wheat
black rust, is capable of causing severe losses and can destroy
entire wheat fields.
It is estimated that as much as 80 percent of all wheat
varieties planted in Asia and Africa are susceptible to this new
strain. The spores of wheat rust are mostly carried by wind over
long distances and across continents.
“Global wheat yields could be at risk if the stem rust spreads
to major wheat producing countries,” said FAO Director-General
Dr Jacques Diouf.
“The fungus can spread rapidly and has the potential to cause
global crop epidemics and wheat harvest losses of several
billion dollars. This could lead to increased wheat prices and
local or regional food shortages. Developing countries that are
relying on wheat and do not have access to resistant varieties
will be particularly hit,” Dr Diouf said.
FAO has joined the International Center for Agricultural
Research in the Dry Areas (ICARDA) and the International Maize
and Wheat Improvement Center (CIMMYT), which are leading the
Global Rust Initiative (GRI), an international consortium to
fight the spread of rust fungus diseases around the world.
Canada, the United States and India are the main donors of the
GRI.
Ug99
The new pathogen first emerged in Uganda in 1999 and is
therefore called Ug99. It subsequently spread to Kenya and
Ethiopia.
A recent FAO mission in the field has confirmed for the first
time that Ug99 has affected wheat fields in Yemen. It appears
that the Ug99 strain found in Yemen is already more virulent
than the one found in East Africa. Samples of the pathogen were
sent to the US and Canada for further analysis. There is a high
risk that the disease could also spread to Sudan.
Past epidemics
Wind-borne transboundary pests and diseases can cause serious
damage to crop production.
In the late 1980s, a virulent strain of the yellow rust, a wheat
disease similar to the stem rust, emerged in East Africa and
crossed the Red Sea into Yemen. It then moved into the Near East
and Central Asia, reaching wheat fields of South Asia within
four years. Major yellow rust epidemics were recorded with wheat
losses of more than one billion US dollars.
Based on the monitoring of the Desert Locust pathways, FAO does
not exclude that wind currents could carry Ug99 stem rust spores
from Yemen northwards along the Red Sea to Egypt or through the
Saudi Arabian Peninsula towards countries in the Near East.
On alert
FAO urges affected countries and countries at risk to increase
their disease surveillance.
Yemen in particular should be on the alert, step up field
monitoring and training and prepare for direct control
interventions in disease hot spots. Most important, control
measures in affected countries should include the introduction
of more resistant wheat varieties and restricting planting dates
to break the disease cycle.
FAO, ICARDA and CIMMYT will support countries in developing
resistant varieties, producing their clean quality seeds,
upgrading national plant protection and plant breeding services
and developing contingency plans.
RELATED INFORMATION
Source: ProMED-mail
<promed@promedmail.org>
[Wheat stem rust is caused by the fungus _Puccinia graminis_. It
occurs worldwide throughout wheat producing areas. Grain is
shriveled due to the damage to the conducting tissue of the
stems. Yield losses of up to 70 percent occur, some fields are
totally destroyed. Dispersal is by wind and with infected straw.
New races are emerging with increased virulence against
resistance genes previously used for breeding new wheat
cultivars -- see <http://www.ars.usda.gov/Main/docs.htm?docid=14649>
for an overview. The most threatening appears to be strain Ug99.
Pictures of symptoms and general information on wheat stem rust
are available at <http://www.ars.usda.gov/Main/docs.htm?docid=9910>
Links
Information on Ug99
<http://www.sciencemag.org/cgi/content/full/315/5820/1786>,
<http://www.pestalert.org/viewNewsAlert.cfm?naid=36>
Global Rust Initiative: <http://www.globalrust.org/>
- Mod.DHA]
[see also
in the
archive:
Wheat stem rust, strain Ug99 - Yemen: 1st report 20070117.0229
Cereal Rust Update - USA (10) 20060811.2258
2006
----
Stem rust, wheat - multicountry: new strains 20060406.1039
2005
----
Wheat stem rust, new strain - Uganda 20050912.2698
2002
----
Wheat stem rust fungus, new virulence genes - So Afr
20020814.5049] |
|
