Yellow-green Mottle Syndrome

Douglas fir needles display yellow blotches that don't cross the midrib, potentially coalescing into yellow needles with drab green midribs. The cause is unknown, possibly genetic or environmental. Affected trees scattered in plantations rarely show disease spread. Some trees recover within 2-3 years; remove persistently affected trees.

Wait to see whether the tree improves. If tree is affected year after year, remove and destroy. Remove infected material promptly and improve growing conditions to limit pathogen spread. Good sanitation, adequate spacing, and proper irrigation practices reduce disease pressure over time.