EDMONTON – Only vigilance and perseverance will keep the deadly Ug99 strain of stem rust from infecting and devastating Canadian wheat crops, said an Agriculture Canada plant pathologist.
“Stem rust is the most dangerous disease known to wheat,” Tom Fetch told farmers at the Farm Tech conference in Edmonton Jan. 26.
Stem rust can destroy a healthy wheat crop in two weeks when wind-borne spores land on a damp wheat crop, ripping holes in the stem.
Most Canadian wheat varieties are susceptible to Ug99, a type of stem rust identified in Uganda in 1999.
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“It will come here. We want to get the resistance before it gets here,” said Fetch, who began testing Canadian wheat varieties in field nurseries in Kenya in 2005.
“Our popular varieties are fully susceptible to Ug99.”
Fetch’s research discovered that the rarely used Peace and Cadillac wheat varieties are highly resistant to Ug99 and could be used as the initial building blocks to develop resistance for other varieties.
“Ninety percent of wheat varieties in the world are susceptible.”
Fetch said Canada must continue its research to develop stem rust resistant lines that can be used in future wheat breeding programs.
He has also joined a global rust initiative to figure out what races of stem rust exist in wheat crops and what germplasm is available for breeding programs.
“I am working to track the movement and virulence of Ug99,” he told farmers.
While Ug99 has spread by wind to Kenya, Ethiopia, Sudan, Yemen, Iran and South Africa, it likely won’t be long before it is discovered in other major wheat producing areas such as India, Pakistan, Turkey and Ukraine.
R.S. Shulka, a wheat breeder at Jawaharial Nehru Krishi Vishwavdiyalaya Agricultural University in Jabalpur, India, said the possible spread of Ug99 to India is a real concern.
“If it comes here we are in a very, very big problem,” said Shulka, who is working to develop stem rust resistant varieties.
“Any new varieties that are near to registration will be tested for Ug99 tolerance.… If it arrives in India, it will be a disaster.”
Fetch said Canadian producers shouldn’t be complacent because of their geographical distance from Africa.
“Ug99 could be brought to North America at any time,” he said.
“People go on safari and come back wearing the same clothes. There is nothing you can do to police that or stop that.”
It’s not the first time farmers and researchers have been worried about stem rust in Canadian crops.
A North American epidemic wiped out wheat crops in the early 1900s, costing millions of dollars.
The Cereal Rust Lab was established in Winnipeg in 1929 to develop rust resistant varieties and work to eradicate the disease.
It was during this work that researchers discovered that the ornamental barberry plant was the host for stem rust.
Train loads of salt were distributed across the Prairies to apply around the roots of the plant and kill it. Barberry has been considered a noxious weed since 1919.
Development of the Thatcher and Selkirk varieties, which had good stem rust resistance, also helped ensure stem rust has not been a problem in Canadian wheat crops.
Fungicides can be used to control the disease if it’s found before resistant varieties are developed, he said.
“If comes here, we should have a few years before it really increases.”
