01 Jul 2019

Denomination of new official race downy mildew in lettuce

With effect from 01 July 2019 the International Bremia Evaluation Board Europe (IBEB-EU) has named a new official race of downy mildew in lettuce, Bl:36EU.

This new race of lettuce downy mildew pathogen (Bremia lactucae, Bl) has been identified in recent years; Bl:36EU was first encountered in Germany in 2016, and over recent years it was found throughout Europe (France, the Netherlands, Italy, Switzerland and Scandinavia).


The International Bremia Evaluation Board (IBEB) is a joint initiative of lettuce breeding companies in USA, France and the Netherlands, University of California-Davis, the Dutch inspection service (Naktuinbouw) and the French National Seed Station (GEVES). IBEB’s mission is to identify new races of Bremia lactucae that pose a significant threat to the American and European lettuce industry and promote the use of standardized race names in communications with growers.

The race identification and nomination is done by regional IBEB committees specific to each continent. For more information see the ISF website.

Managing Downy Mildew

Rijk Zwaan’s lettuce program has a range of varieties resistant to Bl:36EU, other official strains, and in many cases to other local isolates. For the most up to date information on varietal performance and downy mildew, we recommend that growers speak to their local sales representative.

Rijk Zwaan advocates an integrated approach to disease control; resistant varieties are a large part of this, but crop protection agents and hygiene measures are also important to help prevent the development of new downy mildew races. Proper hygiene practices, such as removal of debris and diseased plants, will reduce the spread of downy mildew in crops.

For more information on Bl:36EU, please see the official press release, or contact your local sales representative.

Download Plantum Press Release