White Pine Blister Rust Flashcards
What is the difference between blister rust on stem vs branches?
If on branch no problem, on stem it is lethal.
What happens if blister rust girdles a branch?
Kills branch which will kill itself
What are the types of cankers?
Lethal: on stem or on branch within 15cm of stem because fungus is active beneath bark. From 15-60cm it will kill tree if not pruned.
Non threatening: more than 60 cm from stem.
What does top kill refer to?
If canker high on stem it just kills top.
What was a result of blister rust damage?
Wiped out pw as a viable spp. Genetic advancements have improved resistance.
What are some important positive silvical characteristics of white pine?
Fast growing
Valuable wood
Resistant to DRL
How does age of tree effect resistance?
- Under 20 years old trees are in high danger due to low needles
- over 40 years low danger as needles get higher.
What are uridiniospores?
Orange spotting on currents that are designed to build up disease population.
What are signs and symptoms on ribes?
- Rust spots on underside of leaf
- brown bristles (telial columns) in late summer
What are the signs and symptoms on Pw?
- spindle shaped swelling
- orange spores bursting from bark
- top kill
- red flagging/rodent feeding (sugars)
- diamond shaped spore patch on canker in early stage ( longitudinal growth faster than radial )
- resinosus
- rough Bark
Is tree reacting to blister rust?
No, blister rust attracts secondary pathogens like insects and other fungi by attracting sugars to infection.
What are the hosts and range of blister rust?
Range of soft 5 needle pines
Introduced to North America in early 1900s
Found on soft pines and currants
Is ribies eradication feasible for management?
Effective in east NA and less effective in west but can help at local scale.
How is pruning timed and managed?
2 lifts. First lift: Tree height 2m Prune height 50% Timing in May/June when spores are visible.
2nd lift:
tree height 4-5m
Prune height 50%
FG criteria for blister rust ***
Fails if: canker on stem or canker less than 60 cm from stem on live branch.
What to consider if trying to assess blister rust hazard?
- what kind of currant and how much? [ black, high/ red, mod/ swamp, low)
- dry climate is good because delicate Basidiospores dry out faster.
- gullies are dangerous because of moist
- slopes are bad because they put foliage closer to currant
Where is the risk the lowest and highest in bc for blister?
Lower risk on dry coast above 1000m
High risk in kootenays
Why do we tree breed for for blister rust?
- variation in resistance
- moving trees long distances can cause problems due to seasonal variations but white pine is quite elastic. One breeding program for coast and one for interior.
What are the two schools of thought in breeding for rust resistance?
- single (major gene) resistance
- multiple ( minor gene resistance )
- lose needles early
- infected needles drop
- bark reaction ( toxic chemical produced that resists canker )
What is the goal of breeding for resistance?
65% resistance (survival rate)
No need to prune resistant stock
Management decisions for rust
- mix spp
- genetically resistant stalk
- plant high density
- prune ( 2 lifts to keep branches 2m from ground)
- aim for drier sites if hard pines not an option.
What are the benefits of dense stands where blister rust
- ribes shaded out
- lower branches shaded out and self prune sooner
- Lower branches self prune sooner
- some mortality is acceptable if high density
- benefit is only evident after crown closure and time of most concern.
What is the infection zone of blister rust?
85% of infection below 2 m
What is the lifecycle sequence of white pine blister rust?
Basidiospores 1n Spermatia Aeciospores Urediniospores Teliospores 2n
