OK - I think I can positively identify this for you as I've been trying to bring this under control on my own plum trees and damsons - you have pocket plum. It is closely related to plum leaf curl and you'll often see the two together (although not always). Symptoms include swollen and distorted plums that grow more rapidly in size than normal plums and lack a stone. These infected plums then develop a mildewy coating which infects other plums and so on.
It's a fungal disease. The best control I have found is removal of the affected branches and plums before they develop the mildewy coating and then a spray of bordeaux solution (copper sulphate + slaked lime) twice during dormancy (once in autumn and once before the buds open is spring).
There are some other chemical controls (Westland plant rescue, microbutinol etc.) but bordeaux is really the best solution (snigger) and is organic too
Thanks - I'd identified the problem but hadn't realised that there was an organic remedy. Where do you get Bordeaux solution (or the ingredients for it)?
I haven't seen the mildew on my tree - maybe I cut off the affected fruit etc early enough last year that it didn't have time to develop - but clearly just taking off the affected twigs during the summer isn't enough to prevent recurrence.
On searching further, I was slightly unnerved to find someone quoting the RHS website as saying that,"Bordeaux Mixture will be withdrawn from sale on 28 February 2013 but any person can use and store existing stocks until 28 February 2015." Can't find that on that site now, though.
http://www.rhs.org.uk/advice/pdfs/fungicides-for-home-gardeners emphasises the need to use fungicides only when recommended for the particular purpose. Plum pocket is not the same as "bacterial canker on cherry and plum", which seems to be the only purpose for which Bordeaux mixture is recommended in plum growing.
I wouldn't lisyen to the RHS TBH - Bordeaux mixture has been used for years on Pocket Plum and is a standard treatment across the world. Certainly it's been the norm on most farms for as long as I can remember.
Plus it'll be very, very hard to withdraw Bordeaux from sale as no one I know actually buys it "made up" as it is too expensive and simply doesn't keep. Make it up yourself by buying slaked lime and copper sulphate from a chemical supplier or ebay. Bear in mind that made up this traditional way it needs to be used on the day. You'll find plenty of recipes online for it.
"On searching further, I was slightly unnerved to find someone quoting the RHS website as saying that,"Bordeaux Mixture will be withdrawn from sale on 28 February 2013 but any person can use and store existing stocks until 28 February 2015."
I was so surprised about that RHS guidance I thought I'd look that up and see what they said. Their main page on Pocket Plum actually recommends using Bordeaux so it seems that the original poster may have that confused with another fungicide!
Posts
OK - I think I can positively identify this for you as I've been trying to bring this under control on my own plum trees and damsons - you have pocket plum. It is closely related to plum leaf curl and you'll often see the two together (although not always). Symptoms include swollen and distorted plums that grow more rapidly in size than normal plums and lack a stone. These infected plums then develop a mildewy coating which infects other plums and so on.
It's a fungal disease. The best control I have found is removal of the affected branches and plums before they develop the mildewy coating and then a spray of bordeaux solution (copper sulphate + slaked lime) twice during dormancy (once in autumn and once before the buds open is spring).
There are some other chemical controls (Westland plant rescue, microbutinol etc.) but bordeaux is really the best solution (snigger) and is organic too
Thanks - I'd identified the problem but hadn't realised that there was an organic remedy. Where do you get Bordeaux solution (or the ingredients for it)?
I haven't seen the mildew on my tree - maybe I cut off the affected fruit etc early enough last year that it didn't have time to develop - but clearly just taking off the affected twigs during the summer isn't enough to prevent recurrence.
On searching further, I was slightly unnerved to find someone quoting the RHS website as saying that,"Bordeaux Mixture will be withdrawn from sale on 28 February 2013 but any person can use and store existing stocks until 28 February 2015." Can't find that on that site now, though.
http://www.rhs.org.uk/advice/pdfs/fungicides-for-home-gardeners emphasises the need to use fungicides only when recommended for the particular purpose. Plum pocket is not the same as "bacterial canker on cherry and plum", which seems to be the only purpose for which Bordeaux mixture is recommended in plum growing.
I wouldn't lisyen to the RHS TBH - Bordeaux mixture has been used for years on Pocket Plum and is a standard treatment across the world. Certainly it's been the norm on most farms for as long as I can remember.
http://phytopath.ca/download/cpds-archive/vol41/CPDS_Vol_41_No_3_%28174%291961.pdf
Plus it'll be very, very hard to withdraw Bordeaux from sale as no one I know actually buys it "made up" as it is too expensive and simply doesn't keep. Make it up yourself by buying slaked lime and copper sulphate from a chemical supplier or ebay. Bear in mind that made up this traditional way it needs to be used on the day. You'll find plenty of recipes online for it.
"On searching further, I was slightly unnerved to find someone quoting the RHS website as saying that,"Bordeaux Mixture will be withdrawn from sale on 28 February 2013 but any person can use and store existing stocks until 28 February 2015."
I was so surprised about that RHS guidance I thought I'd look that up and see what they said. Their main page on Pocket Plum actually recommends using Bordeaux so it seems that the original poster may have that confused with another fungicide!
See here: http://www.rhs.org.uk/advice/profile?pid=199