Orange Spots on Maple Branches

Maple Basics

• Maple trees -- scientifically known as Acer -- are most commonly found in Asia, but they also flourish in North America and parts of Western Europe. The plants are characterized by their pointy green leaves and thick foliage. There are more than 200 known species of maple trees and shrubs. Maple trees are quite susceptible to attacks by different types of fungi, mildew and mold. Many of the tree varieties are valued for their rich syrup.

About Tubercularia Canker

• The little orange nodules are the first sign that your tree has been infected by the weak pathogen called Tubercularia canker. This fungal disease typically afflicts stems injured during harsh winter weather and branches with wounds. The disease can be airborne, and it easily is spread from tree to tree. Weaker trees that have not been well maintained are an easy target for the disease. If it is not treated quickly, the odds of survival are not good.

Treatment

• There are ways you can go about attacking this menacing fungal invader. Prune your maple tree during dry weather; cut branches far below the infected area to get rid of all the orange spots. Remove the afflicted branches and destroy them by burning them in a pile or burying them; if you leave them on the ground near the maple tree, it can still spread to other branches. Wash your gardening tools afterward so you don't spread the spores.

Preventing Future Outbreaks

• You can minimize the chances that your tree will get the telltale spots by keeping on top of maintenance. When pruning your maples, don't leave stubs; cuts should be clean and sharp to reduce the risk of infection. Keep your trees healthy by giving them enough water and fertilizer. Refrain from fertilizing your trees during the late part of the summer, because this makes your trees more likely to get injured by delaying dormancy.