date:Aug 06, 2013
emphasizes that although breeding companies supply growers with lettuce varieties possessing resistance to the nominated Bl:1-31 isolates, this is not a full insurance against Bremia. The resistance gives the grower a basic protection. However, occasionally problems may be caused by a local breakthrough of resistance of specific varieties by an isolate that does not survive over years and does not spread to other areas.
The board emphasizes also the importance of chemical control and hygiene me