Wheat researchers use new tool to track Ug99 spread

By MATTHEW WEAVER

Capital Press

Researchers around the world have a new tool to track a virulent strain of stem rust.

The International Maize and Wheat Improvement Center (CIMMYT), based in Mexico, has launched a global wheat rust monitoring website, RustTracker.org .

Eight stem rust races are members of the Ug99 group, the most recent of which was formally identified and reported earlier this year, said David Hodson, a CIMMYT representative in Ethiopia.

The race group is now in 11 countries: Uganda (where it originated), Kenya, Ethiopia, Sudan, Eritrea, Yemen, Iran, Tanzania, Mozambique, Zimbabwe and South Africa.

In 2007, the disease caused the loss of up to 30 percent of Kenya's wheat crop, the biggest epidemic recorded to date.

Major losses have not been seen in other countries, but the race group is so infectious it presents a threat to many major commercial cultivars, Hodson said.

"For any rust epidemic to occur you need a combination of not only the virulent pathogen, but also a susceptible host, a favorable environment and infection early enough to allow an epidemic to develop," he said.

Hodson said the new website's goal is to provide a single source of information about the rust's spread worldwide.

"It is essential to know what changes are happening in other regions, so preventative measures can be taken ahead of time," he said, citing as an example replacement of known susceptible varieties with those resistant to the rust.

Rusts can quickly spread across vast distances, Hodson said, either by wind or by humans. Ug99 will most likely enter the U.S. naturally by crossing the Atlantic Ocean from Africa into South America and then moving northward.

Hodson said CIMMYT works closely with scientists at the USDA Agricultural Research Service Cereals Disease Lab in Minnesota, which coordinates all surveillance activities in the U.S.

Tim Murray, plant pathologist at Washington State University, chairs a committee to develop a recovery plan for Ug99 if it shows up in the U.S. The committee is revising the plan, and work is expected to be completed this fall.

Murray said previous versions of RustTracker focused on Africa and the Middle East. The new site more quickly monitors Ug99's global movements.

In the meantime, scientists are preparing for its eventual arrival.

"The longer it takes for it to get here, the better prepared we are going to be," Murray said. He pointed to U.S. wheat varieties with Ug99 resistance and the availability of fungicides to deal with it.

"We're not all the way there yet," Murray said. "As time goes on, we're worried about it, but maybe not as worried as we were five years ago."

Online

http://rusttracker.cimmyt.org/