Fact Sheets

Douglas Fir: Armillaria root rot

Douglas Fir: Armillaria root rot categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2023-01-31 12:00 White fungal mat of Armillaria root rot infecting trunkPhoto by: C.R. Foss Biology Armillaria root rot is a fungal disease transmitted between plants by root contact. Armillaria is often found in newly cleared soils or ones which have […]

Douglas Fir: Laminated root rot

Douglas Fir: Laminated root rot categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2023-01-31 12:00 Staining in wood (James) and wind-thrown tree (Wallis) R.L. James (wood), G.W. Wallis (tree); Bugwood.org Biology Laminated root rot is a fungal disease of conifers throughout the Pacific Northwest. Douglas-fir, grand fir, and mountain hemlock are highly susceptible […]

Douglas Fir: Rhabdocline needle cast

Douglas Fir: Rhabdocline needle cast categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2024-06-05 02:07 Douglas-fir Rhabdocline needle castPhoto by: R.S. Byther Biology The first symptoms of this fungal infection are many tiny yellow spots on the current season’s needles appearing in late summer or fall. By spring, these spots have expanded and […]

Douglas Fir: Rust

Douglas Fir: Rust categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2023-01-31 12:00 Douglas-fir Melampsora rustPhoto by: G.A. Chastanger Biology Rust is a fungal disease infecting the needles of Douglas fir. Wind-blown spores infect the new needles in the spring. Yellow to orange bumps, or pustules, are found on the underside of needles […]

Douglas Fir: Stem cankers

Douglas Fir: Stem cankers categories: Conifers Douglas Fir Diseases Ornamentals revision date: 2023-01-31 12:00 Douglas-fir stem cankerPhoto by: Unknown Biology Stem cankers on Douglas fir are sunken and oval, occurring on branches or new shoots. Each canker is typically centered around a dead twig and can be small or up to 30″ long or more. […]

Douglas Fir: Swiss needle cast

Douglas Fir: Swiss needle cast categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2024-06-05 02:07 Douglas-fir Swiss needle castPhoto by: R.S. Byther Biology This fungal disease causes infected needles to become off-color and mottled yellow or brown. The needles may turn completely brown and are usually dropped prematurely, often in early spring. Infected […]

Douglas Fir: Upper stem canker

Douglas Fir: Upper stem canker categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2024-06-05 02:07 Douglas-fir upper stem cankerPhoto by: R.S. Byther Biology Upper stem cankers are caused by fungi in the soil. Seedling Douglas fir trees are affected, with the tops of infected trees turning yellow. By fall, the tops turn reddish-brown. […]

Douglas Fir: Yellow-green mottle syndrome

Douglas Fir: Yellow-green mottle syndrome categories: Conifers Douglas Fir Douglas Fir Diseases Ornamentals revision date: 2024-07-10 01:13 Douglas-fir yellow-green mottle syndromePhoto by: G.A. Chastanger Biology The cause of yellow-green mottle syndrome is unknown but may be genetic. Needles of all ages are affected by yellow-green mottle syndrome. Yellow-green blotches may be small or may cover […]