Other Stem Rusts

Other Stem Rusts
- Native Cronartium
  - Comandra (DSC), Stalactiform (DSS), [Sweet Fern]
  - Hosts & Range - Pl (Py) <--> HERBS (toad-flax, paint brush) ... thru' out range of hosts
  - Infection & Spread - same as DSB (except obviously the hosts)
  - Sporadic Wave Years (3 factors)
    - 1) large release of spores when ...
    - 2) lotsa susceptible tissue and ...
    - 3) env. conditions (temp/moist) are just right
    - ... epidemics ...
      - warm moist front passes in late summer
      - outbreaks are localized
      - hard to predict
    - danger - wave years in young stands
      - many stands escape wave years
      - some have 1 wave year ... bad
      - few have several ... really bad
  - Life Cycle
    - Pine
      - spermatia (pycniospores) - fertilize
      - aecio - infect alt host
    - Alt Host
      - uridinio - intensify
      - telio - finish genetic exchange
      - basidio - infect pine needle
  - Damage
    - young stands
      - mainly 5-30 years old
        
        peaks at 15 years
        
        declines 15-30 years
        
        rare 30+ years
        
        graph ...
    - mortality
      - most stem infections <1m
      - thinning agent
      - wave years - NSR patches
    - squirrels preferentially feed on cankers
  - S&S
    - same as DSB
      - diamond shape canker
      - spindle-shaped swelling
      - rough bark
      - resin drops
      - yellow/ orange spores in May-June
      - branch flagging/ top kill
      - rodent (insect) feeding
  - Mgmt
    - @ harvest ... well ...
      - mix spp. (always a good idea)
      - higher density
        
        compensate for mortality
        
        reduce alt. host
        
        speed self-pruning
        
        BUT ...
    - @ FG/ JS
      - notes on timing & sanitation
        
        rust peaks @ 15 years ...
        
        ... if spacing is done early (12-15 years) ...
        
        ... then a wave year ... yikes!
        
        best to consider hazard rating & local incidence
        
        sanitation ...
        
        we "aim" to sanitize, but ...
        
        many infections will be missed ...
        
        ... also future infections can still happen
      - Hazard & JS
        
        LOW - if JS
        
        timing? "sanitation success"
        
        favour mix spp.
        
        MODERATE - if JS, as above & LEAVE EXTRA
        
        <15 years
        
        extra = 2* infection rate
        
        >15 years
        
        extra = infection rate * stocking
        
        e.g. target = 1,000sph & infection = 25%
        
        HIGH
        
        delay JS until after 15+ yr & disease subsides
        
        or ... "just say no"
      - FG criteria: lethal canker
        
        on stem
        
        <60cm from stem on live branch
- Endocronartium (DSG)
  - Hosts & Range - Pl (Py), BC
  - Infection & Spread
    - NO alt. host
    - aeciospores infect flushing buds (epidermis, no periderm)
  - Wave Years
  - Damage
    - young stands - most stem infections 1-10yrs
    - mortality
      - NOT effective thinning agent
        
        infected trees keep growing
        
        using water & nutrients
        
        but eventually break in wind
        
        "that volume" could have been grown on adjacent trees
      - wave yr - could result in NSR
    - branch galls 5+cm
      - non-lethal
      - no serious growth impact
      - BUT source of spores
  - S&S
  - Mgmt
    - @ harvest ...
      - mixed spp., esp. in high hazard areas
      - higher density if concerned ... "suffer mortality"
    - @ FG/ JS
      - FG criteria: lethal canker
        
        on stem
        
        <5 cm from stem
      - JS after 10 yr ("leader in the clear") ... JS in May/June? (sanitation)