- White Pine Blister Rust
- Biology
- History
- intro from Asia to Europe (~1850's)
- Intro to NY 1905, to Vancouver 1910
- Hosts & Range
- range of soft (5-needle) pines
- Ribies (currants)
- Infection & Spread
- basidiospores [1n] (late summer/fall) - produced on Ribies, infects Pw (needle via stomata)
- pycniospores (spermatia) [1n] (early spring) - "fertilization" occurs ~2 years after infection
- aeciospores [n+n] (late spring, next year)- infects 2º host (Ribies)
- urediniospores [n+n] (spring summer) - increases infection on 2º host
- dry vs. wet summer
- rusty
- teliospores [2n] (late summer) - 'completes sex' to produce basidio
- basidiospores [1n] (late summer/fall) - infects 1º host
- ~85% are < 2m ht
- delicate
- need moist/ warm conditions
- The Canker
- infection zone: ~85% <2m
- spread - 5-10cm/yr long. / 1-3 cm/yr radial
- if kills branch ... no problem
- if on stem ... problem
- old branch?
- low vigour
- no needles close to stem
- natural prune?
- girdle branch before stem if >60cm
- types of cankers
- lethal
- on stem
- visible on branch <15 cm (already in stem)
- 15-60 cm if no prune
- threatening (treatable)
- 15-60 cm if pruning
- non-threatening
- >60cm - kills branch before getting to stem
- Damage
- lower stem - mortality
- upper stem - top kill
- "wiped out" Pw as a viable spp. - but now have genetically improved stock
- white pine
- fast growing
- valuable wood
- resistant to DRL
- Age of Tree
- < 20 yr - high danger - needles ...
- > 40 yr - low danger - needles ...
- Signs & Symptoms
- Ribies
- Pw
-
- hazard rating (not fully dev. for BC)
- Ribies
- how much?
- spp.? (black=good host, red=mod., swamp=poor host)
- proximity? (<50m = bad)
- climate
- dry summer/fall ... good - spores dry out/ die faster
- gullies ... not good - moist & ht of infection
- steep slope - height of infection
- Officially in BC H&R=H everywhere
- but 1000+m on coast - lower H&R
- Harvesting
- winter - limit disturbance & Ribies colonization
- partial harvest ... shade ... less Ribies
- site prep - burn? (only if hot & complete)
- Ribies eradication
- 1930's-70's
- but
- root respout
- seed bank
- seed rain
- seems to be effective in east NA
- less effective in west, but ...
- brushing "helps" at a local scale
- dense stands
- lower branches less vigorous & less foliage
- lower branches self prune sooner
- Ribies shaded out
- more trees - "suffer greater mortality"
- BUT ...
- pruning
- good if
- few infections > 2m
- Pw is young & even-aged
- prune - 2 lifts
- 1st Lift ... tree = ~2m
- 2nd lift ... tree = 4-5m
- "standards"
- prune ht = 50% of tree ht (65% coast)
- timing ... late spring vs autumn
- prune
- flush to branch collar, not stem
- ALL branches below critical ht
- ... even in duff
- + INFECTED branches above critical ht
- lethal infections - no prune
- FG Criteria
- canker on stem
- canker <60cm from stem on live branch
- tree breeding
- why
- variation in resistence exists
- lack of strong provenance (i.e. only 2 programs needed: coast & interior)
- how
- single - "major" gene resistance
- no cankers = RESISTANCE
- Cr2 stock
- partial "minor" gene resistance
- = "contained infection" = TOLERANCE
- (infected) needle shed
- difficult to infect
- bark reaction - Pw "contains" canker
- fast height growth =EVASION (escape)
- ~65% resistance (50-100%)
- "no need to prune"
- monitor (... if cankers ...)
- other
- canker scribing (excising)
- girdle the canker
- 20cm by 5cm "buffer"
- smaller cankers
- high value trees - urban setting
- fungicides - not operational
- biological - hyperparasite (Tuberculinia maxima) - does not kill active margin
- quarantine - too late
- nursery mgmt - important
- hey, why are there "more Pw" in a swamp?
