Ug99: No more cheap white bread

by Kathy Purdy on April 7, 2007 · 1 comment

According to the Cereal Disease Laboratory, there is an emerging virulent stem rust race that is infecting supposedly rust-resistant strains of wheat. It is called Ug99 because it was first discovered in Uganda in 1999. SeedQuest says that

About 70 percent of U.S. wheat varieties are thought to be susceptible to Ug99. Between 70 and 75 percent of wheat grown in India and Pakistan are also susceptible to this rust, and wheat in Egypt and China is thought to have similar vulnerabilities.

According to the New Scientist website,

Black stem rust itself is nothing new. It has been a major blight on wheat production since the rise of agriculture, and the Romans even prayed to a stem rust god, Robigus. It can reduce a field of ripening grain to a dead, tangled mass, and vast outbreaks regularly used to rip through wheat regions. The last to hit the North American breadbasket, in 1954, wiped out 40 per cent of the crop. In the cold war both the US and the Soviet Union stockpiled stem rust spores as a biological weapon.

It would be worth your while to read all three websites. Thanks to the Ethereal Voice for bringing this to my attention. After checking out the New Scientist article, I googled Ug99 and couldn’t find any encouraging information. (I’m always a bit suspicious of hysteria.) What I want to know is, is there anything a home gardener can do?

I'm always pleased when the garden is neat and tidy. That's when it looks like a garden. Nature is plants and the complicated ecosystems that support them. But even the most natural of gardens is an unnatural arrangement of plants. We stamp our will upon the landscape, even those of us who prefer to work with nature. And often, like this weekend, nature stamps back. Maybe it's that dramatic tension between artfulness and chaos that keeps us coming back to the garden. Or maybe it's just the flowers and blue skies and finding two little snakes under a rock.

M. Sinclair Stevens

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1 Julian Thomas March 10, 2008 at 10:43 am: The rust characterised as Ug99 has now spread out of Africa to Yemen (2006) and onto Iran (2007). Testing in Kenya suggests that most North American varieties are susceptible. In Canada we only have two varieties that display a high level of resistance.

Of course Ug99 and its derivatives are presently not in North America but are now within striking distance of the large acreages of wheat on the Indian subcontinent and then on to China. The destruction wrought on a susceptible variety by a stem rust epidemic is indeed something to see. Testing in Kenya has shown that the availability of effective resistance sources among experimental varieties (ie. avilable for breeding resistant varieties) is also quite limited. The most likely scenario for stem rust to arrive in Noerth America is that it will be walked in unintentionally by someone travelling on a airplane. This for instance is how stripe rust recently arrived in Australia.

The world wide genetic vulnerability of common wheat to this race of stem rust is hard to exaggerate. Durum (pasta wheat) however appears to be more resistant.

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