Plantation Pests

Plantation Pests
- Black Army Cutworm IDA
  - H&R
    - conifer seedlings, Fd, Sx & (Pl) most common
    - interior (ICH, MS, SBS, ESSF)
    - burned sites
    - notable outbreaks 20 intervals (last 4 yrs)
    - (damaging on dry sites)
  - Biology
    - lepidoptera ...
    - moths fly late summer (late summer), attracted to sites burned w/in 12 mo.
      - burn May-July ... damage next spring
      - burn Aug-Oct ... damage in 2nd spring
      - which is likely to have more damage to seedlings?
    - eggs in ash ... hatch in fall, larva OW in duff
    - start feeding @ snow melt ... shot holes
    - prefer herbs ... seedlings if no herbs or high pop'n
    - early instars feed day, older feed night (hide in day)
    - patchy distrb'n in block (0.25-1 ha)
    - L1-L6 (L6 can defol. seedling in 2 days)
    - pupate in loose soil (~5cm)
  - S&S
    - shot holes in foliage after snow melt
    - defol of herbs & seedlings
    - larva - black w 2 sets of double white lines each side
  - Damage
    - 1st year plantation at risk
    - factors for outbreak on seedlings
      - site burned in the last year
      - high pop'n
      - few herbs
      - fresh seedlings
    - outbreak <> damage ...
    - factor for damage
      - >60% defol, and/or
      - terminal bud killed
      - moist. stress
        
        dry site
        
        dry summer
        
        poor planting
        
        seedling in poor condition
    - the problem
      - defol seedlings have poor root growth
      - hence problem with moist stress
      - ... poor ht growth ... brush
      - ... predisposition ... other pathogens/pests
      - mortality if heavy defol (>60%)
        
        ~40% if moist. stress
        
        ~15% if no moist. stress
  - Mgmt ??
    - ID susc sites
      - interior BC (ICH, SBS, MS, ESSF)
      - dry - shallow/ coarse soil; south-facing
      - burned in last year
    - monitor pop'n
      - pheromone traps in summer/fall
      - <350 = Low ... "no problem"
      - 350-1200 = Mod. ... ground check in spring
      - >1200 = High ... ground check or cancel
    - ground check @ snow melt
      - shot holes - no plant
        
        cancel, plant next year
        
        delay 'til July (?) or fall plant
      - no holes - recheck in 1 week
        
        holes, see above
        
        no holes, no worries
    - other thoughts
      - if fall burn ... plant immediately
        
        seedlings get fall & next year to establish
        
        also time for herbs to establish
      - if spring burn & mod-high pop'n expected
        
        consider delay planting 1 yr ...
        
        esp. if it's a dry site
- Conifer Seedling Weevil IWC
  - H&R
    - seedlings (esp. 1 yr) - Fd & Ss (H, B & Cw)
    - coast (CWH) and interior wet belt (ICH)
    - mainly w. VI & QCI
  - Biology
    - long lived - larva 2 yr, adult 3-4 yr (flightless)
    - eggs ... larva ~2 yr on phloem of roots ... adult ~3-4 yrs herbs (seedlings)
    - feed on herbs & seedling root collar
    - sporatic outbreaks
    - logging creates habitat (stumps)
    - prefers "veal"
      - nursery > naturals
      - plug > bareroot stock
      - 1 yr > 2 yr seedlings
    - pop'n grows by 2nd/3rd yr ...
      - damage if only seedlings & no herbs
      - typically if planting adjacent to opening 3 yrs old
  - S&S
    - scattered mortality of seedlings
    - girdling at base
  - Damage
    - partially girdled seedlings usu. recover
    - mortality if >90% girdled
  - Mgmt
    - damage is sporadic ...
    - ... so almost all the time ... nothing
    - if weevil damage noted nearby ? ...
      - plant 1 yr after harvest to avoid damage
      - if damage ... fill plant with 2-0 stock
- Warren's Root Collar Weevil IWW
  - H&R
    - Pl (Sx)
      - 20% of Pl stands in BC - higher in central interior
      - stand with IWW has 40-80+% trees attacked
      - starts attack when trees 1m tall (2cm dia) ... prefer larger stems
      - continues thru to mature
    - Interior
      - moist sites
      - deep duff
      - coarse textured soil (SL)
      - shaded
  - Biology
    - long lived - larva 2 yr, adult ~5 yr
    - life cycle
      - eggs laid in summer
      - hatch, larva feed on roots - pitch/soil/frass shelter
      - OW as larva
      - larva feeds all next yr
      - OW again
      - larva feeds ... pupate in summer ... adult
    - adult is flightless - just walks :)
      - nocturnally feeds in trees (bark, buds)
    - logging
      - adults move out to surrounding timber
      - re-invade after trees ~ 2cm diam/ ~1 m tall
      - 13m / yr
  - S&S
    - larva = white grub (2cm at maturity)
    - (adult = weevil, black w gray scales, long snout)
    - foliage
      - young trees ... straw ... red
      - older trees ... chlorotic
    - stunted terminal (reduced growth)
    - leaning trees / easy to pull out
    - girdling @ root collar
    - "kitty litter" = pitch + soil + frass
    - pattern - starts at periphery
      - trees 1st attacked ~ 5 yrs (1m)
      - S&S noticable by 10-15 years ... FG time
  - Damage
    - young tree
      - girdle @ root collar ... mortality
      - 1-2 larva / tree
      - 5-20 yr ... up to 80% trees affected ... 5% (0-10%) mortality
      - mortality as single trees or small groups, usu. close to mature edge
      - increased mort. adj. to MPB killed stand
    - older trees
      - larger root collar ... larva on 1º roots
      - some roots girdled (not collar)
      - ↓ increment (10-30%)
      - ↑ susc. to root disease (DRT)/ drought
  - Mgmt
    - review ... it likes
      - Pl
      - interior
      - moist site
      - coarse soil
      - deep duff
      - shaded conditions
    - @ regen
      - in mod-high hazard subzones
        
        do a root weevil assessment
        
        include all adj. pine type in block
        
        migration to adj. stand less successful
        
        reduced re-invasion
      - mix spp.
      - higher density ... "suffer more mortality" & shade
      - remove duff - burn, scarify, large screef
      - IF fill plant ... not Pl
    - @ FG/ JS
      - trees attacked by IWW (>1/3 circum) not FG
      - delay JS until 20+yr
- European Shoot Tip Moth ISE
  - H&R
    - (hard) pines
    - BC: lower mainland, Victoria - Parksville
    - introduced (1914 e US, 1959 reported in PNW)
  - Biology
    - lepidoptera ...
    - eggs in summer at branch tips & leader
    - larva mine needles, then bud to OW
    - feeding within branch tip continues in spring .. pupate ... adult
  - S&S
    - shoot/ terminal damage (shepherd's crook)
    - webbing
    - resin
  - Damage
    - not yet sig in operational forests in BC
    - concern for interior
      - under (Canada) Plant Protection Act
      - no transfer of pine foliage to interior
      - annual inspections
    - quarantines in some US states (CA, NV MT)
  - Mgmt
    - operational forest in BC - nothing
    - nursery/ ornamentals - clipping, insecticides (flight & L1)
- Pitch Moths ISQ & ISP
  - General
    - lepidoptera ...
    - attack pine shoots
    - tree reaction is pitch = 'igloo'
    - damage is deformities to stem & breakage
    - FG issue if 30cm displace. @ >30cm ht
  - Sequoia Pitch Moth ISQ
    - s 1/2 of BC
    - pines 2+ m tall
    - larva - 2 yrs, adult - days
    - FG issue if 30cm displacement @ >30cm
  - Northern Pitch Twig Moth ISP
    - e of Coast mtns
    - pines 0.3 - 3(10)m tall
    - eggs hatch on leader, early larva feed @ site, small pitch blob
    - next spring feeding resumes, June larva move to 2nd location down at branch crotch