18 May 2015

New race of downy mildew in lettuce receives official designation

The International Bremia Evaluation Board (IBEB) has officially designated a new race of downy mildew in lettuce: Bl:32.

Much more widespread in Europe

This isolate was already known, but has now become much more widespread in Europe, according to research by the IBEB into the Bremia isolates identified in 2014 and earlier. Most outbreaks of Bremia caused by these new isolates have only local consequences. In recent years, however, Bl:32 has been identified in France, Germany, The Netherlands, the United Kingdom, Austria, Switzerland and Belgium, and it has recently also spread to Portugal and northern Spain.

The large majority of Rijk Zwaan’s Bl:16-31-resistant varieties are also resistant to this new race.

Rijk Zwaan lettuce on the field