DISEASE ALERT – DOWNY MILDEW ON COLUMN STOCKS

Over that past couple of weeks there has been a serious issue with downy mildew in column stocks. The problem was first seen in Holland a month or two ago and led to some crops being unmarketable. At the moment very little detail is known about the biology of this particular strain of downy mildew, if indeed it is a new strain. However what has become clear is that it is much more “aggressive” than what we are used to and there are anecdotal reports (especially from Holland) that it may be resistant to some of the fungicides that are regularly used for downy mildew control. It has also become apparent that a 7 to 10 day spray interval is not adequate and may need to be reduced to 5 days. Growers are advised to contact their agronomist for further details about a suitable spray programme.
The CFC is currently working with the industry to try and determine as much information as possible about this problem and is currently in discussion with scientists about the possibility of developing a resistance testing facility for the chemicals used to control downy mildew.  More details will be posted on the website as they become available.