Transcript Armillaria
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 Causal Agents: • • • • • • • • • Armillaria ostoyae A. mellea A. gallica A. nabsnona A. gemini A. calvescens A. cepistipes XI A. sinapina NABS IX, X 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 damaged Moderately damaged Seldom 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: death Infection level 100% total root colonization Armillaria Phellinus Years since infection decay Control strategies include: • Reducing inoculum - < 30% slope - low hazard for mass wasting, erosion, compaction, etc. 1987 1977 2002 1992 Control strategies (cont.): - Alternate species Severely damaged Moderately damaged Seldom 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 *no difference in susceptibility in trees less than 15 years old Strategies (cont.); 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. Other strategies: - Biological control *Operational effectiveness not yet proven. *Inadequate delivery. *No agents yet registered. Hypholoma fasciculare Stand development Chemical control with Sporax or Tim-Bor recommended on: -dry pine sites -all true fir sites -mixed conifer sites where true fir is favored R R 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.