Time to Watch for Fusiform Rust

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One of our Master Gardener℠ volunteers in Craven County has forwarded a nice image of fusiform rust on a young loblolly pine, and this is definitely the time of year (early April) when we see a lot of these bright orange or yellow-orange sporulating “rust galls”. The gall tissue is weak compared to healthy wood tissue, and as explained in a plant pathology note from NC State University, infected pines often break at the point of a gall as the trees become larger.

April is a good time to evaluate the pines on your property. If fusiform galls are on side branches and are at least 12 inches from the trunk, then pruning out these branches could provide effective control. However, if the galls are within 12 inches or actually on the trunk, the tree should be removed. This is especially the case if the tree is located within striking distance of a home or other target.

To encourage the vigor of individual pines and reduce the likelihood of pine beetle attack and other problems, consider thinning residential pine stands to a distance of at least 20 feet between individual trees. Removing pines that have been compromised by fusiform would be a great way to begin that process.

fusiform rust

Early April is a good time to check loblolly pines (Pinus taeda) for sporulating galls caused by the fusiform rust pathogen. Photo by John Wright.