A yellow rust “watch list”, alerting growers of winter wheat varieties that are likely to perform below their headline disease ratings, has been issued by the AHDB.
The online list aims to flag up unusual levels of yellow rust seen in some variety trials based on a cultivar’s usual resistance rating.
This will help growers to better understand disease risk, monitor at-risk crops more closely, and fine-tune management strategies for the season.
How it works
Catherine Harries, manager of disease research at the AHDB, explains how the online wheat yellow rust list provides a way to flag-up unfamiliar varietal disease levels.
“This extra layer of information can provide a valuable early warning of a potential change in the UK’s race structure and help focus in-season management strategies,” she says.
The watch list orders varieties based on disease levels from the three worst-performing Recommended List (RL) trials for each variety, with three categories used to describe their performance.
These are: highly resistant varieties, medium-resistant varieties and low-resistant varieties. Zyatt, Wolverine, Kerrin, Kinetic and Skyfall winter wheat crops are at the greatest threat from yellow rust (see below).
It follows the development of a new rating calculation approach that better reflects the diverse and dynamic nature of the UK’s rust populations.
However, currently, the watch list order broadly agrees with the headline disease resistant ratings.
“As the situation can change rapidly, it is important to monitor all crops closely and report unexpected levels of disease to the UK Cereal Pathogen Virulence Survey,” warns Ms Harries.
To access the watch list and the Recommended List 2021-22 booklet visit: ahdb.org.uk/rl.
The most susceptible varieties to one or more yellow rust races present in some trials are listed below.
Growers are advised to monitor these varieties frequently and be prepared to increase use of rust-active fungicides in the programme.
Winter wheat varieties with low resistance to yellow rust:
Source: AHDB 2020-21 Recommended List. *on a scale of 1-9 where 9 shows highest resistance.
Pathogens survey meeting
Discussions on the latest twists and turns in the yellow rust story will feature as part of a UK Cereal Pathogen Virulence Survey stakeholder meeting to be held online on 12 March 2021.
The survey was set up to detect and warn the industry about new races of rust and mildew that are capable of causing disease on previously resistant cereal varieties.
Targeted at breeders, crop scientists and technical agronomists, the annual stakeholder meeting reports on results from recent Niab-led screens.