DRA Flashcards
What are the susceptible hosts of Armillaria?
Fd, B,S, Hw
What are the resistant trees to DRA?
- Lw
- Cw
- Hardwoods
What should we remember when using Lw as an alt. spp?
Early mortality due to fast root growth while tree is vulnerable
What is the most resistant tree to DRA?
Cw
What is something to remember about hardwoods as alt spp?
Resistance decreases as time goes on. Go for a short rotation.
What is the difference between Coast vs Interior DRA?
- Interior wet belt - Universally present (Trees are healthier and disease is diffuse)
- Coast - (not significant (mortality up to 15 years))
- Rest of Interior - disease centers evident (1-10 ha)
What will decide tree mortality by DRA?
The relative strength of trees will ultimately decide whether DRA can kill them or not.
How does armillaria infect trees?
Spores rare, infection via root contact or “rhizomorph”
What is the common name for DRA? why?
Shoestring fungus. If roots are close but not touching, DRA creates a bridge to the healthy root.
What are the characteristics of DRA mycelium?
Endotrophic mycelium (live in bark/cambium - mycelial fans)
What parts of the tree can DRA inhabit?
- Sapwood (CODIT reactions)
- In heartwood when present in large roots
- Operates in all tissues
What is the rate of spread of DRA?
about 10cm / year in BC. Has a slower rate of spread than phellinus because it likes to go inside the tree.
How does harvesting increase innoculum potential of DRA?
Trees natural defenses are removed and DRA goes into a flare up, gaining strength off the available food that it now does not need to fight for.
What is innoculum potential dependent on in DRA?
- Available food increases innoculum potential
- When DRA is battling a tree its innoculum potential decreases
Quiescent vs Active DRA
Quiescent disease centers in wetbelt
Active disease centers in the rest of the interior
On the coast the disease centers are active in the juvenile stage but become quiescent as the trees gain strength.
