I have a plum tree that has black balls on the branches and is almost now...

Asked June 20, 2014, 10:48 AM EDT

I have a plum tree that has black balls on the branches and is almost now totally dead. I am having it removed and I wonder if it is safe to plant another tree nearby?

Carroll County Maryland

1 Response

From your description, it sounds like your plum tree is suffering from a fungal disease commonly known as 'black knot'. The disease is progressive, so, for future reference, the simplest control strategy is to prune out the affected branches 6-8 inches below the affected area and destroy the cuttings. This should be done annually when the tree is normally pruned and before the knots become very large.
If the disease has progressed too far, it would be best to remove the tree.
You can plant another in the same area, but monitor it annually for disease and insects. Fungal diseases, such as black knot, can be prevented by spraying susceptible trees with a suitable fungicide annually, following a rather extensive regimen, beginning when the buds break in the spring and applying fairly regular cover sprays throughout the fruiting season.
LS