Recommended List (RL) 2020/21 winter wheat disease ratings for yellow rust and brown rust have been released ahead of the full RL following reports of higher than expected disease levels in some commercial varieties during the 2018/19 growing season.
RL yellow rust and brown rust trial data were subject to additional checks which found varietal resistance to these diseases was, generally, in line with recent years.
As a result, the revised ratings feature no major changes for most varieties.
The varieties KWS Zyatt, Bennington and Viscount all saw a fall in yellow rust resistance, and KWS Firefly and Viscount fell for brown rust resistance.
However, LG Spotlight and LG Skyscraper showed improved levels of resistance to brown rust.
Unexpectedly high levels of disease on some varieties in 2018/19 could reflect the emergence of a new race(s) at a local scale, says AHDB.
A clearer picture will be available when the UK Cereal Pathogen Virulence Survey (UKCPVS) completes analysis of samples sent in during the 2018/19 season.
If higher than expected rust levels are seen, an infected leaf sample should be sent to the UKCPVS for testing: ahdb.org.uk/ukcpvs