What is it?
Cytospora canker is caused by the fungus Leucostoma kunzei, which attacks conifers such as Colorado spruce, Norway spruce, Douglas-fir, and white pine. The spores can be spread via birds, insects, rain, and wind. This fungus is often present in healthy branches, but the disease typically begins in stressed trees.
Symptoms
- The infection start at the bottom and gradually process up.
- Needles turn brown or purplish-brown, and eventually drop.
- White or bluish resin covered on dead diseased areas.
- Damage is usually seen on older, larger trees.
Damages
- The canker rarely kill the tree, but it will deform the tree severely.
- The tree loses its aesthetic value.
- Stressed tree are more prone to disease.
What to do?
- Keep your tree healthy with mulch and regular watering to help it withstand attacks.
- Avoid unnecessary pruning that creates wound for disease entry.
- Remove and dispose infected branches in winter or dry periods.
- Sanitize your pruning tools.
- No chemical treatment is effective.
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