22/04/2011

In the UK the threat from yellow rust has significantly increased with more moderately susceptible varieties being affected over the past week. At a conference in Syria, scientists discussed the threat to affected global regions posed by new strains of rust.

Crop Monitor has shown first observations of yellow rust this season at sites in Norfolk, York, Telford (Shropshire) and Hampshire, while the disease is progressing in areas already affected. Infection is said to be extending from the highly susceptible varieties, including Oakley, Robigus and Solstice, into those more moderately susceptible, such as Viscount, Duxford, Glasgow and Cordiale.

On 18^th April, the risk of yellow rust was reported to have increased significantly. According to Crop Monitor about half of the weather stations monitored had recorded medium or high risk conditions and eight of the Live Monitoring sites were affected by yellow rust.

Agronomists have warned late drilled and stressed crops, particularly following roots, have shown increasing signs of the disease, and the sustained dry, warm weather with heavy dews appears to have increased the severity of the situation.

New aggressive rust strains threaten parts of Africa and Asia

Elsewhere in the world, Researchers meeting at a scientific conference in Aleppo, Syria this week reported that aggressive new strains of wheat rust diseases – called stem rust and stripe rust – have decimated up to 40% of farmers' wheat fields in recent harvests. Areas affected are North Africa, the Middle East, Central Asia and the Caucuses, including Syria, Egypt, Yemen, Turkey, Iran, Uzbekistan, Morocco, Ethiopia, and Kenya.

“These epidemics increase the price of food and pose a real threat to rural livelihoods and regional food security,” said Mahmoud Solh, Director General of the International Centre for Agricultural Research in the Dry Areas (ICARDA).

In most of the countries in Africa, the Middle East, and Central Asia and the Caucuses, where wheat can contribute more than 40% of people's food calories and 20% of the protein, the epidemics cause economic hardship for farmers and their families.

Climate change, in terms of rising temperatures, and the timing and increasing variability of rainfall, is contributing to the spread and severity of rust diseases. Emerging races of rust are showing adaptations to extreme temperatures not seen before. Scientists around the globe are working on monitoring and surveillance of stem rust and stripe rust to insure rapid detection and reporting so farmers, policymakers, and agricultural research centres can respond more quickly to initial outbreaks.

 “There is need for enhancing in-country capacity of the breeding, seed and extension systems to continuously ensure that new, highly productive and genetically diverse resistant varieties are available and accepted by farmers to meet the challenges of changing rust virulence,” said Wafa El Khoury, coordinator of the Wheat Rust Disease Global Program at the Food and Agricultural Organization (FAO). “Coordination and timely information sharing among all the stakeholders—from surveillance and plant protection officers, to wheat breeders, seed system and extension agents, and farmers—is key.”