Common Root Pathogens

Laminated root rot (DRL) pathogen

Phellinus sulphuracens

Laminated root rot (DRL) range and hosts

Present in southern BC up to Pringe George

Douglas Fir & Subapline Fir (high)

Spruce, hemlock & larch (moderate)

Hardwoods (resistant or immune)

Laminated root rot (DRL) signs and symptoms

Red/ brown setal hypha between laminated sheets

Ectotrophic mycelium

Resupinate conk (crust-like) on roots, stumps, logs

Laminated root rot (DRL) root decay

Incipient: Red-brown stains in sapwood

Advanced: Softened wood, rings will seperate to form sheets

Laminated root rot (DRL) spread

Infection on wounded or healthy roots

Spread through root contact (ectotrophic mycelium)

Spore spread is uncommon

Tomentosus root disease (DRT) pathogen

Onnia tomentosa

Laminated root rot (DRL) range and hosts

Entirety of BC

Spruce and lodgepole pine (high)

Douglas Fir (moderate)

Hardwoods (immune)

Laminated root rot (DRL) signs and symptoms

Basidiocarp polypores conks

Ectotrophic mycelium

Laminated root rot (DRL) root decay

Incipient: Dark-red-brown stain in heartwood

Advanced: White longitudinal pockets

Laminated root rot (DRL) spread

Spore

Root contact

Annosus root rot (DRA) pathogen

Heterobasidion occidentale

Annosus root rot (DRA) range and hosts

Southern BC and South West BC up to Prince George

Spruce, Hemlock & Subalpine Fir (high)

Douglas Fir & Cedar (moderate)

Hardwoods (immune)

Annosus root rot (DRA) signs and symptoms

Shelf-like resupinate conks on underside of roots or base of tree

Ectotrophic mycelium

Annosus root rot (DRA) root decay

Incipient: Yellow-brown stain of sapwood and heartwood

Advanced: White stringy decay with black spots

Final: Wood degraded with a hollow butt

Annosus root rot (DRA) spread

Spores on fresh wounds

Root contact

Armillaria root disease pathogen

Armillaria ostoya

Armillaria root disease range and hosts

Southern BC up to Prince George

Douglas Fir, Subalpine Fir & Spruce (high)

Hemlock & Lodgepole Pine (moderate)

All other species are suseptible

Armillaria root disease signs

Mycelial fans

Dark rhizomorphs (melanin)

Honey mushrooms (cream and yellow coloured)

Armillaria root disease stand level symptoms

Mortality pockets with epicenters

Mixture species inclucing hardwoods

Bark beetle attack on weak trees

Armillaria root disease local spread

Mycelium root to root contact

Rhizomorph on roots reaching out

Expanding existing infection pocket

Armillaria root disease long distance spread

Basidiospores from mushrooms create new infection pockets

Requires exposed or damaged wood

Armillaria root disease as a primary pathogen

Causes disease and death in healthy trees

Infect young trees (<15 yrs)

Old hosts of highly susceptible species

Armillaria root disease as a secondary pathogen

Opportunistic and cause death/ decay in weak trees

Old/ stressed trees of non-susceptible species

Armillaria root disease mechanical root penetration

Hypha from rhizomorph tip exerts pressure on root

Melanin strengthens cell walls

Armillaria root disease chemical root penetration

Enzyme cocktail

Degrade cell walls and act on all wood polymers

Armillaria root disease Facultative mode

Facultative parasite while tree is alive (pathogenic)

Armillaria root disease Saprotophic mode

Saprotrophic when tree is dead

Decays wood and causes white rot

Remains for up to 50 years

Tree defenses to Armillaria root disease

Traumatic resin ducts

Necrophylactic periderm (creates dense. more protective layers under original periderm to block pathogen)

Management of Armillaria root disease

Regen with less susceptible species

Stump removal

Hardwood regen

Pushover harvesting