Pine: Western gall rust

Biology

Western gall rust affects primarily two- and three-needle pines, including shore, lodgepole, mugo, Scotch, Austrian, and ponderosa pines. This fungal disease causes small to large round or pear-shaped galls on infected twigs, branches, or trunks. The galls persist and enlarge each year. Branch tips beyond the galls become stunted and bushy and may die. In the spring, two-year-old and older galls are covered with orange or yellow-orange spores, which cause new infections on young shoots of susceptible trees. Large galls can weaken the trunk or major limbs, making them highly susceptible to breakage.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Prune out and destroy galls from infected trees.
• If the gall occurs on the trunk, it may be possible to prune the tree back and train a new leader to replace the diseased portion. However, it may be necessary to remove the tree for safety’s sake.
• Remove infected trees from pine stands.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended

Additional Image