Symptoms include: Chlorotic (yellow) needles “Stress” cone crop Reduced height growth

Windthrow, snags and stubs

Fungi spread primarily through and along roots.

Armillaria root disease caused by A. ostoyae

Armillaria ostoyae A. mellea A. gallica A. nabsnona A. gemini A. calvescens A. cepistipes XI A. sinapina NABS IX, X Causal Agents:

Symptoms and signs: - Resin on the bark surface - white mycelial fan

Armillaria root rot

Armillaria travels through the soil via rhizomorphs

Species susceptibility to A. ostoyae Severely damagedModerately damagedSeldom damaged East-side Douglas-fir Grand fir White fir West-side Douglas-fir Ponderosa pine Lodgepole pine Western white pine Sugar pine Pacific silver fir Noble fir Subalpine fir California red fir Western hemlock Mountain hemlock Engelmann spruce Sitka spruce Western redcedar Western larch Incense cedar Port Orford cedar

De-laminated wood of laminated root rot

Phellinus weirii on bark of infected root

Ectotrophic mycelium Setal hyphae (red whiskers)

Fruitbody of Phellinus weirii

Susceptibility to laminated root rot: Highly susceptible: Douglas-fir Grand fir Mountain hemlock Intermediately susceptible: Subalpine fir Western larch Tolerant: Lodgepole pine Western white pine Resistant: Ponderosa pine Western redcedar Immune: All hardwoods are immune

Annosus root disease Heterobasidion annosum

Spores of asexual form of H. annosum on infected wood

Annosus root disease found on all western conifers Primary concern is on: -true fir (s-type) -hemlock (s-type) -pine (p-type)

Infection in a root system: Infection level Years since infection death decay total root colonization 100% Armillaria Phellinus

Control strategies include: Reducing inoculum - < 30% slope - low hazard for mass wasting, erosion, compaction, etc.

Severely damagedModerately damagedSeldom damaged East-side Douglas-fir Grand fir White fir West-side Douglas-fir Ponderosa pine Lodgepole pine Western white pine Sugar pine Pacific silver fir Noble fir Subalpine fir California red fir Western hemlock Mountain hemlock Engelmann spruce Sitka spruce Western redcedar Western larch Incense cedar Port Orford cedar Control strategies (cont.): - Alternate species *no difference in susceptibility in trees less than 15 years old

Wildfire: - has little effect on belowground Armillaria sp. - may displace fire-intolerant hosts Strategies (cont.);

- Fertilization *Nitrogen - may delay symptoms *Potassium – alters root phenol:sugar

Strategies (cont.): - Chemical agents *effectiveness demonstrated on single stumps. *curatives likely uneconomical.

- Biological control Hypholoma fasciculare Other strategies: * Operational effectiveness not yet proven. *Inadequate delivery. *No agents yet registered.

Stand development

Chemical control with Sporax R or Tim-Bor R recommended on: -dry pine sites -all true fir sites -mixed conifer sites where true fir is favored Minimum stump size for treatment is ca. 10 inches

Compares: - future stand conditions and productivity. - effects of inoculum on management objectives. - effects of silvicultural prescriptions.