Plum armillaria root rot, also known as mushroom root rot, oak root rot, honey toadstool, or bootlace fungus, is an extremely destructive fungal disease that affects a variety of trees. Unfortunately, saving a plum tree with armillaria is unlikely. Although scientists are hard at work, no effective treatments are available at this time. The best recourse is to take steps to prevent oak root rot on plum. Read on for more information and helpful tips.
Symptoms of Oak Root Rot on Plum
A tree with plum oak root fungus generally displays yellowing, cup-shaped leaves and stunted growth. At first look, plum armillaria root rot looks much like severe drought stress. If you look closer, you’ll see rotted stems and roots with black, stringy strands developing on larger roots. A creamy white or yellowish, felt-like fungal growth is visible under the bark.
Death of the tree may occur rapidly after symptoms appear, or you may see a gradual, slow decline. After the tree has died, clusters of honey-colored toadstools grow from the base, generally showing up in late spring and summer.
Armillaria root rot of plums spreads primarily by contact, when a diseased root grows through the soil and touches a healthy root. In some cases, airborne spores can spread the disease to unhealthy, dead, or damaged wood.
Preventing Armillaria Root Rot of Plums
Never plant plum trees in soil that has been affected by armillaria root rot. Keep in mind that the fungus can remain deep in the soil for decades. Plant trees in well-drained soil. Trees in consistently soggy soil are more prone to oak root fungus and other forms of root rot.
Water trees well, as trees stressed by drought are more likely to develop the fungus. However, beware of overwatering. Water deeply, then allow the soil to dry before watering again.
Fertilize plum trees in late winter or early spring.
If possible, replace diseased trees with those known to be resistant. Examples include: