DUBAI, 27 March 2008 (IRIN) - The Ug99 strain of the
killer wheat fungus (stem rust), which recently infected wheat farms in
western Iran, is a serious threat to global
food security, agricultural scientists have warned. They have said the fungus
may affect additional wheat-producing countries.
Pakistan's wheat crop is vital to the country's 160
million inhabitants. With the long distance travel of rust spores, Ug99
could soon affect farms in the Middle East, Central Asia, South Asia and
Mahmoud Solh, director-general of the International Centre for Agricultural
Research in the Dry Areas (ICARDA),
was quoted in a 20 March ICARDA press release as saying that he and his fellow
scientists were convinced that Ug99 would quickly spread beyond Iran and that,
with the long distance travel of rust spores, Ug99 would soon affect farms in
the Middle East, Central Asia, South Asia and East Asia.
Richard Brettell, director of the Biodiversity and Integrated Gene Management
Programme at ICARDA, told IRIN on 26 March that halting the spread of the stem
rust spores is difficult since they are dispersed by the wind. "The fungus can
to some extent be controlled by the application of fungicides [as a spray];
however, these need to be applied at an early stage of infection before the
disease takes hold," he said.
Brettell said the most effective way of controlling the disease is to grow
resistant varieties. But he warned: "The problem is that almost all the wheat
varieties grown in West and South Asia are known to be susceptible to Ug99. It
will take time and coordination to replace them with resistant varieties."
The UN Food and Agriculture Organization (FAO)
warned in early March that the major wheat-producing countries to the east of
Iran should be on high alert. Other areas likely to be affected include the
Mediterranean region, north Africa, southern Europe, eastern Europe and Russia.
International Centre for Agricultural Research in the Dry Areas (ICARDA)
ICARDA, established in
1977, is one of 15 international research centres supported by the
Consultative Group on International Agricultural Research.
ICARDA serves the entire developing world for the improvement of barley,
lentils, and fava (broad) beans; and dry-area developing countries for
the on-farm management of water, improvement of nutrition and
productivity of small ruminants (sheep and goats), and the
rehabilitation and management of rangelands.
In the central and west Asia and north Africa regions, ICARDA is
responsible for the improvement of durum and bread wheat, chickpeas,
pasture and forage legumes and farming systems; and for the protection
and enhancement of the natural resource base of water, land and
According to ICARDA, sporadic epidemics of stem rust, also known as black rust,
have plagued wheat production before. It cites an outbreak of the disease in
North America in the 1950s which destroyed up to 40 percent of the spring wheat
crop. Since the discovery of Ug99 in Uganda in 1999, the fungus has infected
crops in north and east African countries and in early 2006 it was found in
Yemen as had been predicted based on earlier
movements of yellow rust.
Brettell said the pathogen had moved faster than anticipated because it had been
able to take a hold on susceptible wheat varieties grown in the Arabian
peninsula. "These provided a bridge for it to jump to Iran, most likely being
blown by prevailing winds," Brettell said.
Before its appearance in Iran, a country with six
million hectares of wheat, stem rust had seriously affected wheat production in
Ethiopia, Kenya and Yemen. ICARDA's Solh said that since the pathogen was moving
faster than anticipated, surveillance, monitoring and tracking of this new
strain was essential for control of the disease.
A close up of wheat stem rust
Brettell explained why Ug99 had defeated varieties that had been resistant to
stem rust in the past: The rust fungus had a capacity to mutate and take on new
virulence, in a similar way to other pathogens, such as the influenza virus for
animals (including birds) and humans. "Ug99 is a new variant of the wheat stem
rust pathogen... The problem arises because this new variant has overcome the
resistance bred into many of the world's wheat varieties," he said.
Following the detection of the fungus in Iran, a two-day Stem Rust Baseline
Survey Workshop on Standardising Protocols and International Collaboration was
held at ICARDA, Aleppo, Syria, on 10-11 March. It was jointly organised by
ICARDA, the International Maize and Wheat Improvement Centre (CIMMYT), FAO and
Cornell University, under the Borlaug Global Rust initiative.
The purpose of the meeting was to standardise
methods for surveying and tracking the spread of stem rust Ug99, as well as to
strengthen international collaboration to combat it.
Consultative Group on International
Agricultural Research (CGIAR)
The Consultative Group on
International Agricultural Research (CGIAR) is a strategic alliance of
countries, international and regional organisations, and private
foundations supporting 15 international research centres that mobilise
cutting-edge science to promote sustainable development by reducing
hunger and poverty, improving human nutrition and health, and protecting
This, said Brettell, was achieved by bringing together about 49 scientists and
researchers from the national agricultural research institutes of Egypt,
Eritrea, Ethiopia, Iran, Kenya, Morocco, Nepal, Pakistan, Sudan, Syria, Tunisia,
Turkey, Uruguay and Yemen. A number of international research institutes also
attended the workshop.
ICARDA is putting much emphasis on international cooperation and sharing of
knowledge, saying that the fight against Ug99 must be a global effort.
A Global Rust Initiative (GRI) was launched in 2005, and both ICARDA and CIMMYT
have been working closely with the US Department of Agriculture, Agriculture
Canada, FAO and other national and international organisations to limit the
spread of Ug99.
Both ICARDA and CIMMYT have identified resistant wheat varieties, and these are
currently under evaluation in national agricultural systems around the world,
according to Brettell.
In October 2007 scientists and researchers met in Addis Ababa, Ethiopia and
established an early warning system to check the spread of stem rust. A survey
system was then set up that would help researchers track and identify the spread
of the fungus.
The above article comes to you via IRIN, a UN humanitarian information unit, but may not necessarily reflect the views of the United Nations or its agencies. © UN Office for the Coordination of Humanitarian Affairs 2008
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