Crown rust alert for grass leys

11 Oct 2010

Crown rust infection of rye grassGrass quality could be at risk from crown rust infection if the unseasonably warm weather continues, warns NIAB TAG.

Bright orange crown rust pustules have been visible on perennial rye grass plots at NIAB TAG trial centres across the UK for several weeks. Crown rust reduces the quality and energy available from grass, and in the very worst cases infected grass will be rejected by grazing animals.

Worryingly the disease has been seen out of its normal geographical range more frequently over the past decade; a possible sign that climate conditions are favouring a more northerly distribution.

“Autumn crown rust infection is not unusual in the south and south west of England, but the levels recorded at more northerly sites is cause for concern. Some varieties are showing up to 15% leaf area infection at the Harper Adams trials site in Shropshire,” says Dr Thomas, pathologist at NIAB TAG.

Plant resistance is the main method of control with future implications on variety choice in seeds mixtures. Resistance to the disease is evaluated during National List trialling, funded by Fera, and in Recommended List trials, supported by breeders, seed merchants, EBLEX and DairyCo.

“Many perennial ryegrass varieties have good resistance to crown rust and there should be something suitable for every situation. Incorporating a proportion of resistant material in a seeds mixture will offer protection against the worst effects of crown rust.

“Traditionally, the emphasis used to be on ensuring grass seed mixtures for the south west contained sufficient resistant types, but now it looks as though crown rust resistance will have to be considered further north,” suggests Dr Thomas.

NIAB recommends grassland farmers consult merchants who participate in the Grass Levy Scheme to receive the most up-to-date technical information on crown rust resistance. A comprehensive variety guide is also provided by BSPB on

For further information contact:
Dr Jane Thomas, Head of Field Crops Research, NIAB
T: 01223 342251
E: jane.thomas [at] ()

Issued by:
Ros Lloyd, FrontFoot Communications
T: 01487 831425
M: 07711 568164
E: ros.lloyd [at] ()