RECENT REPORTS of mildew infection in some crops of Robigus have raised concerns that a new mildew race may be developing, says National Institute for Agricultural Botany.

The variety currently has a mildew resistance rating of nine, and until now has remained free from the disease, said NIAB’s Dawn Muddyman.

Isolated cases of the disease have been found in Robigus across the UK, prompting the UK Cereal Pathogen Virulence Survey to call for growers to report any sightings of mildew in this variety.

But Simon Francis from breeders CPB Twyford stressed that these were isolated cases and there is no reason for growers to be concerned.

“This is not a panic situation and if growers haven’t found it by now then they haven’t got it.”

While mildew has been found in some Robigus, it is in low levels and is generally restricted to stressed crops, he said. The disease mutates very quickly, so it is not the variety’s resistance that’s changing, he added.

Even where growers had not planned a mildew treatment at T1, the infection will be no worse than a variety such as Einstein, which is rated seven for the disease, he noted.

Any growers who have live mildew on Robigus can send sample leaves to NIAB. Samples should be wrapped in dampened blotting paper, sealed in a polythene bag and sent first class to:

Mrs Amy Skellern
UKCPVS
Plant Pathology
NIAB
Huntingdon Road
Cambridge
CB3 0LE