Trees are always under a variety of stresses due to the environment. The stress factors can range from nutrient deficiencies, storm damage, and even poor service practices. Under normal conditions, trees are fairly well equipped to handle these stresses and in most cases can recover. However, during prolonged drought conditions a tree’s resources are often exhausted trying to tolerate the lack of available water.
While pest and disease are a continual part of a tree’s natural life cycle, trees are much more susceptible to damage when drought stressed. One disease in particular that should be expected to become a bigger problem through the hot dry summer is Seiridium canker disease.
Seiridium canker disease is caused by Seiridium unicorne and it most commonly affects Leyland and Italian cypress trees. Plants of all sizes and ages are affected. Cankers may form on stems, branches and in branch axils causing twig, branch or stem dieback. Cankers will appear sunken, dark brown or purplish patches on the bark, often accompanied by extensive resin flow. However, resin flow often occurs from the branches and stems of otherwise healthy plants of Leyland cypress, so resin flow by itself may not be confirmation of a Seiridium canker disease.
Scattered twigs or branches destroyed by the fungus turn bright reddish brown and are in contrast to the dark green healthy foliage .Fruiting bodies of the fungus appear on the bark surface of the cankers as small circular black dots barely visible to the naked eye. Spores of the fungus are spread to other parts of an infected tree, or from tree to tree by water splash from rain or irrigation.
If you need help or advice with Seiridium Canker Disease, don’t hesitate in scheduling time with an ISA certified arborist.