A disease causing branch dieback in many species of conifers, particularly in Colorado blue spruce.
This disease also attacks other two and three needled pines such as mugo, Scots, and red pines.
- Dead branches
- Dying branches (needles of infected branches change colour)
- Pitch oozing from infected branches and stems
Cytospora attacks weakened trees that are growing under stressful conditions. Stress can be caused by many factors (root damage, poor soil conditions, heat, salt), but especially by drought.
There is no direct cure for cytospora. It is important to remember that cytospora attacks weakened trees, so methods of treatment should focus on improving the tree’s health. Making the tree healthier may enable it to prevent further advancement of the disease. Cultural practices such as pruning dead and dying branches, fertilizing, mulching and watering will help to improve the tree’s health. Note that a watering program should extend into the fall season because the roots of most conifers grow more at that time than at any other.