Global stem rust tracker unveiled in China

A global monitoring system was unveiled to track the spread of devastating wheat pathogens known as stem rusts, at the 2012 Borlaug Global Rust Initiative (BGRI) Technical Workshop in China.

The functional surveillance and monitoring network, the Global Cereal Rust Monitoring System ('Rust Tracker'), now covers 27 countries and a large proportion of the developing world's wheat acreage, according to an international team of scientists from countries including Ethiopia, Mexico and Syria.

Stem or cereal rusts are caused by fungi that affect wheat, attacking the plants outer layers, causing infections which result in fewer tillers and seed being produced, and leading to plants breaking, shriveling, and, in severe cases, dying. The pathogens represent a major threat to global food security, particularly in the developing world.

"New technologies are playing an increasingly important role in rust tracking," the scientists said, listing dynamic visualisation tools and new web resources as examples. "These are already having an impact in several different areas, from survey data collection to pathogen diagnostics, and their role is likely to increase in the future."

Dave Hodson, developer of the Rust Tracker, and a senior scientist at the Ethiopian office of the International Maize and Wheat Improvement Center (CIMMYT), said that mobile devices, such as smartphones and tablets, are now used for field data collection.

A special focus is cast on monitoring the Ug99 group of stem rusts, first detected in Uganda in 1999, which represents a major threat to global wheat production, as the fungi are quickly mutating and spreading across the world's wheat fields.

"We have found the Ug99 lineage has eight races, which have spread to various wheat-growing countries in Iran, South Africa, Sudan, Yemen and Zimbabwe," said Hodson. "Its spread to other countries in Africa, Asia, and beyond, is inevitable."

But it is very difficult to know where Ug99 will be found next, researchers say.

Ug99 migrated to Iran through the wind, with wind models indicating that it will most likely continue to migrate towards South Asia. Only strong vigilance and cooperative surveillance on a global level will detect it, researchers say.

"Wind models show that air parcels can move from Yemen to South Asia in three days," Hodson said.

"The vast wheat-growing region that stretches across North Africa and Central Asia all the way to the gateway to China — the world's largest wheat-growing nation — is still vulnerable," said Ronnie Coffman, director of the Durable Rust Resistance in Wheat Project and vice chair of the Borlaug Global Rust Initiative.

And Wan-Quan Chen, vice head of the Institute of Plant Protection at the Chinese Academy of Agricultural Sciences, who highlighted the progress of Chinese scientists in fighting the stem rust said: "Most Chinese wheat cultivars — more than 90 per cent of them — are susceptible to Ug99".

The next steps for stem rust surveillance will include an expansion of the geographic coverage of the surveillance network, increasing capacity for collaborating partners — by introducing new tools, for example — and an expansion to cover other rust diseases in more detail, said Hodson.

Ravi Prakash Singh, head of the Irrigated Bread Wheat Improvement and Rust Research programme at CIMMYT's Mexico office said that progress in tackling the rust was evident.

But, he warned, "Wheat fields in a significant number of countries remain largely unprotected from the dangerous pathogen".