1. Uganda 99 Black Stem Rust Yue Jin
Uganda 99 Black stem rust of wheat was first notice in Uganda in It is spread by wind and passes its heterecious stage in the ample Berberis species in the region. It has spread quickly into Yemen and Iran, threatening
the immense wheat production areas of Pakistan, India, and China.
Yue Jin

2. Uganda 99 Wheat Rust Epidemiology
2001 Kenya
2003 Ethiopia
2007 Yemen
IRAN 2008
Cyclone Gonu
hit the Arabian
Peninsula on
June 8, 2007
2008 Iran

3. Uganda 99 Black Stem Rust
Stem rust fungus is the most feared wheat disease
Wind born
Produces 100 billion urediospores per hectare
Can destroy a crop of wheat in 3 weeks
Outbreaks of stem rust hit North America in 1905, 1916, and
Extensive USDA and CIMMYT resistance breeding
1999 in Uganda a new race appeared: Ug99
Spread into Sudan, Ethiopia, Yemen, and Iran
The last major outbreaks of stem rust occurred in North America between 1950 and 1954, when losses approached 40 percent of the spring wheat production in some years. Since then, with the exception of a few smaller outbreaks, "Wheat stem rust [has] dropped off the radar screen completely," said Ward. "We have a whole generation of plant breeders who don't even know what it looks like."
But to the horror of breeders in a Ugandan nursery in 1999, Ug99 pustules were found covering wheat varieties carrying genes that stem rust had never defeated before. "We now know that Ug99 defeats more of the known stem rust resistance genes than [in] any other [previous] stem rust race," said Ward.
In a fight against time, plant breeders are working to develop and test new wheat varieties at national research facilities in the Rift Valley in Kenya and in Ethiopia, the only places where field testing with Ug99 is safe. Using traditional plant breeding (as opposed to transgenic engineering), breeders are using the research facilities to accelerate the creation and distribution of resistant wheat varieties.
Poor farmers in Ug99's path who cannot afford fungicides or crop losses are especially dependent on the fruits of wheat breeders' labors. The solution, according to Ward, is no small task. "It sounds extraordinary to say, but what we need to do is replace much of the wheat in the world with wheat that is resistant to this race of stem rust," he said.

4. Life Cycle of Puccinia graminis
Aecium 2N
Aeciospores 2N (infects wheat)
(sexual recombination)
Life Cycle of Puccinia graminis
Berberis Leaf
Spermogonium
(two mating types
Uredospores 1N
Basidiospores 1N
(two mating types)
to Berberis
Teliospores 1N
photos courtesy of the University of Hawaii

6. Berberis vulgaris – Barberry Alternate host for Puccinia graminis
Includes genera:
Berberis
Mahonia
x Mahoberberis
over 500 species
Albert Roodink
Native to Eurasia
Brought to North America as a medicinal and culinary plant
Anton de Bary proved that it as the alternate host for cereal rusts in 1865
Eradication programs in the US, including
2 native species
De Bary did a thorough investigation on Puccinia graminis, the pathogen of rust of wheat, rye and other grains. He noticed that P. graminis produced reddish summer spores called "urediospore", and dark winter spores called "teleutospores". He inoculated sporidia from the winter spores of the wheat rust on the leaves of the "common barberry" (Berberiso vulgaris). The sporidia germinated and led to the formation of aecia with yellow spores—that was the familiar symptoms of infection on the barberry. De Bary then inoculated aecidiospores on moisture-retaining slides, then inoculated these to the leaves of seedling of rye plants. In time, he observed the reddish summer spores appeared in the leaves. The sporidia from the winter spores germinated, but only on barberry. De Bary clearly demonstrated that P. graminis required different hosts during the different stages of its development (a phenomenon he called "heteroecism" in contrast to "autoecism", when development take place only in one host). De Bary’s discovery explained why the eradication of the barberry plants had long been practiced as a control for rust.
Wikipedia
Zereshk - Dried fruit of
B. vulgaris, a much favored
delicacy of Iran

7. Berberis vulgaris In 1920, the USDA Barberry eradication program began
jaki good
WY 1990
Barberry distribution in US & Canada
Birds are the number one vector of Barberry seed. The states in the eradication survey have to keep checking to see if Barberry stands have been
re-established by bird transmission of the seed or by dormant seeds in the
soil germinating.
Wyoming was added to the survey in 1990
Barberry quarantine area of the United States
In 1920, the USDA Barberry eradication program began
a farm to farm survey covering 750,000 sq miles.
By 1933 over 18 million bushes had been destroyed.
Canada began its program in the Prairie Provinces in1910