Plum Tree Disease

Asked September 14, 2018, 7:31 PM EDT

Our plum tree has some infestation and seems to be dying. Is there any remedy to kill the infestation and save the tree?

Forsyth County Georgia

4 Responses

This is most likely a fungal disease called black knot. It is a frequent problem with plum trees. A combination of pruning out the diseased parts, sanitation (cleaning up and disposing if infected branches as well as dropped fruit and fallen leaves, and cleaning pruning blades between each cut with a solution of 1 part bleach to 10 parts water), and timely application of fungicides may help you save the tree. Pruning should be done during the dormant season, usually late February to early March. Follow label directions for fungicide applications. For more information, see: https://www.ppws.vt.edu/extension/plant-disease-clinic/disease-advisory/Archives/201412-Black_Knot_o...

Can we do the pruning now instead of later in February. I am asking this again because this infestation of fungus has already pretty much spread to 80 % of the tree.

Can we do the pruning now instead of later in February. I am asking this again because this infestation of fungus has already pretty much spread to 80 % of the tree.

Pruning at this point in the season, when trees are beginning to slow growth and drop leaves in preparation for the dormant season, is not recommended. Pruning stimulates new growth, which can be damaged when the first frost arrives in late October. You can prune earlier in the winter, say around December, after the tree is fully dormant. However, doing so leaves pruning wounds open longer, making the tree more susceptible to pest and disease infestations.