29 November 1996

Yellow rust fears soothed

By Charles Abel

YELLOW rust risks in winter wheat were being played down at the show by leading breeder Zeneca.

It announced the results of a survey which shows growers and advisers are confident they can keep on top of the disease, despite the discovery of a new race which can overcome the popular Yr17 resistance gene.

"An overwhelming proportion of growers in both the core and non-core yellow rust areas say they will not be making any major changes to their varietal mix as a result of the appearance of Yr17 ," said commercial manager Alan Armstrong.

The survey showed just 28% of growers in non-core yellow rust areas planned to change their variety choice due to Yr17 this autumn.

The figure was similar in prime yellow rust areas and only 18% of consultants were advising a change, noted Mr Armstrong.

"Compared with the days of Slejpner 10 years ago farmers are much more able to check their crops for diseases and control them. They have a lot of confidence in todays chemicals," continued Mr Armstrong.

"Growers know that varieties like Brigadier which are more susceptible to Yr17 are also the varieties which, year on year, provide them with the best yields and the best financial returns," he said. "They accept that yellow rust is still a problem in some years and in some areas, and that it probably always will be.

Treatments available

"But they are also secure in the knowledge that they now have the treatments to ensure that even in the worst of yellow rust years, more susceptible, but higher yielding varieties will come out more profitably than the less susceptible varieties with lower potential for yield."

Whats more, most growers (40-47%) considered septoria the most expensive disease to control. In non-rust areas mildew came second and in core areas yellow rust was considered most expensive by 20% of growers.

Farmers most used to dealing with the problem found yellow rust very easy to control. Only 10% found it difficult. "That reflects the availability of some first class chemicals," said Mr Armstrong.

Most growers (60%) only have problems controlling yellow rust in one year in four or less. Over 50% have problems controlling septoria and mildew every other year

ZENECA will be asking NIAB why its new winter wheat Harrier failed to secure recommendation on the new HGCA recommended list. It matches other similar varieties for yield – the main criteria for recommendation.

The failure of new malting barley Spice to get on the list was also disappointing, but Mr Armstrong stressed that contracts were in place for malting.

Survey data shows farmers are unworried by the Yr17 reistance-busting strain of yellow rust, said Zenecas Alan Armstrong.