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Black knot disease on purple plum

Posted: Mon Jan 16, 2017 3:34 pm
by Gardener fred
What type of fungicide should I use when treating black knot disease on my purple plum?

Re: Black knot disease on purple plum

Posted: Mon Feb 13, 2017 11:44 am
by lorijones
It is important to first prune out any branches that contain knots. Prune at least 2" - 4" below the knot. This should be done now - during the dormant season. Be sure to burn or discard the pruned branches so the fungal spores cannot reinfect the tree.
Fungicides may be helpful as a preventative but only if the knots are first removed through pruning. Products containing chlorothalonil such as Bonide Fung-onil or a copper spray such as Bonide Copper Fungicide may help prevent the spread of the disease. Here is some more information on this fungal disease: http://inthegardenradio.com/v.php?pg=334. Good luck - it can be hard to control.

Re: Black knot disease on purple plum

Posted: Mon Feb 13, 2017 8:31 pm
by Gardener fred
Thank you for the information!

Re: Black knot disease on purple plum

Posted: Sat Feb 16, 2019 8:44 am
by Jerryknott
This problem could be due to the appearance of some insect on the flower. This plant may have infected with insects and are spreading the infection all over the roots and to the other flowers also. To get rid of these pest issues you can try out using some pesticide sprays or can also contact the pest exterminator UES for some help in this problem.