Increased risks of disease epidemics on cereal crops addressed in Denmark, July 5-8

Wednesday, July 8, 2015

Helsingør, Denmark: Scientists from all over the world met July 5-8, 2015, in Helsingør, Denmark, to discuss challenges and solutions in fighting spreading disease epidemics on cereal crops that may hugely impact worldwide crop production.

“Wheat is the most widely cultivated food crop in the world, while rust and powdery mildew diseases are major constraints for food production,” said Mogens S. Hovmøller, professor in the department of agroecology at Aarhus University, leader of the Global Rust Reference Centre (GRRC) in Denmark, and chief organizer of the conference. “To combat diseases with long-distance dispersal capacities requires collaboration on a global scale and rapid sharing of information among world leading researchers, plant breeders and extension workers.”

Leading experts in plant disease from 33 countries all over the world met at the 14th International Cereal Rusts and Powdery Mildews Conference 2015 in Helsingør, organized by Aarhus University, to discuss challenges and solutions to reducing the risks of disease epidemics and crop losses. Speakers reported about the worldwide landscape of the diseases, innovative control measures, and implications for integrated disease management through strengthening national, regional and global collaborations.

One of the keynote speakers, Sajid Ali from the University of Agriculture, Peshawar, Pakistan, a visiting researcher at Aarhus, reported about the recent spread of invasive strains of yellow rust into Europe from the center of diversity in the Himalayas. New strains have increased the risks of early onset of disease epidemics, which has implication for wheat production and, not least, for organic farming.

“We have good evidence that the new invasion of yellow rust into Europe was spread by rust spores carried by wind from Asia to Europe, possibly through the northern part of Central Asia. The yellow rust fungus is genetically very diverse in the Himalayas, where it can infect wheat and barley as well as common barberry, the sexual host of the fungus,” said Ali.  “The invasive strains were detected already in the first year of appearance in Europe using innovative diagnostic and information technology tools, which enabled early warning and preparedness to face the challenges.”

“Early detection and response were only possible due to long-term collaborations led by scientists from Aarhus University with National Agricultural Research Institute France, Julius Kühn Institute Germany, National Institute for Agricultural Botany United Kingdom, International Wheat and Maize Improvement Centre Mexico, International Centre of Agricultural Research in the Dry Areas and the University of Agriculture Peshawar, Pakistan,” Hovmøller emphasized.

“Rust and powdery mildew fungi have long distance migration capacity, resulting in the spread of invasive strains/races from one region to the other. Since 2011, the European population of yellow rust has been gradually replaced by new invasive strains. We have just completed a huge study involving 12 European countries based on rust samples collected over 15 years, where we analyzed the European results in a global context. The most economic and environmentally friendly solution will be to intensify the development of new crop varieties, which possess resistance to a wide array of plant pathogens and their variants,” said Hovmøller.

These results were recently accepted for publication in the prestigious British journal “Plant Pathology,” so Hovmøller was extremely pleased to be able to present the results at the conference.

In the context of invasions, while breeding for resistant varieties, plant breeders must consider pathogen diversity beyond national boundaries. This will require intensified collaboration between plant breeders and plant pathologists, which was one of the aims of the conference.

There is need both for innovative durable disease resistance genes and smart strategies for the deployment of resistant crop varieties, said Hovmøller.

“Our goal will be to keep the disease at a level where the crop losses are at minimum, while protecting the environment with a justified use of pesticides,” Hovmøller expressed, noting that it was important that leading scientists in plant disease management from around the world could meet in Denmark and discuss issues so closely related to the issue of food security.

“Under the Borlaug Global Rust Initiative, Aarhus University is responsible for storing, analyzing and visualization of global wheat rust data. The database provides information on rust situation and diversity in virulences and pathotypes on user friendly web-based maps and graphics through the GRRC web site ( and RustTracker ( covering Africa and Asia,” said Jens G. Hansen, who is responsible for the database at GRRC. “Collating all data in one database in a structured and harmonized way leads to more robust conclusions, and promotes uptake, ensures usability and guarantees sustainability.”

On the last day of the conference, participants visited the experimental cereal varieties trials demonstrating huge differences in susceptibility to cereal powdery mildew, rust and leaf blotch diseases, at the facilities of the Global Rust Reference Center at the Aarhus Research Centre in Flakkebjerg, Denmark.

James Brown of the John Innes Centre in England, who is chairman of the European and Mediterranean Cereal Rust Foundation (EMCRF), which supported the conference in Helsingør, commented, “This project is a superb example of how collaboration among scientists on three continents has revealed pathways by which aggressive strains of a dangerous disease have spread. Dr Hovmøller’s paper is a wake-up call to national and international plant health authorities to improve measures to reduce the risks of spread of plant disease.”

Read the scientific article “Worldwide spread of wheat yellow rust from the centre of diversity in Himalayas” in Plant Pathology. (  )