Warren's Root Collar Weevil Flashcards
For reference on Warren’s Root Collar Weevil, please see the SEDA –> http://www.forest-insects.umn.edu/pdfs/2009/09McCullochBCJEM10.pdf
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What is the three letter code for Warren’s Root Collar Weevil?
IWW
What kind of site does IWW like?
Moist, shady, deep duff, coarse textured soil.
High hazard for the Interior - particularly SBS and ICH wetter subzones.
What species does IWW eat?
Mostly lodgepole pine, some spruce too.
When is a lodgepole pine susceptible to attack?
At 5 years up until it is mature, attack starts when the sapling is a metre tall.
How much of British Columbia’s forest stands are currently dealing with IWW?
20% (on average) of British Columbia’s Pine stands have IWW
What is the % of trees within a stand that are attacked if IWW is present?
40-80% of susceptible species may be attacked
What does the life cycle of IWW look like?
Eggs are laid in summer.
How long do the Larva stay in the duff?
Larva overwinter for two years in the duff while eating roots.
How long does an adult IWW survive?
Flightless adults survive for five more years.
How does logging affect IWW outbreaks?
IWW moves out of the cutblock into surrounding timber and comes back once regen has hit 2 cm DBH or 1 m height.
Describe the signs of IWW.
Signs: 2cm long white grub larva, dark grey flecked adults with long snouts. (like tiny elephants)
Describe the symptoms of IWW
Symptoms: chlorotic foliage, leaning, root and root collar girdling, and ‘kitty litter’ (pitch mixed with frass and soil) caused by larval feeding.
In what pattern does IWW attack an area?
From outside to inside.
How does IWW damage young trees (5-20yrs)?
Root collar girdling. A young tree is ok with one or two larvae but any more will cause it to die a horrible death.
How does MPB relate to IWW?
Damage is greater from IWW when the area is next to beetle kill stands.
How does IWW damage older trees?
It moves to the primary roots, girdling these instead. Damage creates susceptibility to things such as drought, MPB, and root diseases like tomentosus or armillaria.
How would you manage for IWW?
Survey for signs through examining roots and include adjacent pine stands in your cutblock.
How might site prep help manage for IWW?
You can use site prep like burning, disc trenching or mounding to reduce the duff layer.
What precautions might you take when it comes time to plant?
When planting, delay for 2-3 years since the weevil lives in stumps, plant more to compensate for loss, or fill plant with anything but pine please.
How would you manage for IWW at the Free-to-Grow/Juvenile Spacing stage?
Check for signs and symptoms. Any tree with IWW is not FG.
Delay spacing until 20 years or more.
In a test, what are some key terms about IWW that can help you?
Interior pine, duff layer, kitty litter, root collar young - death, roots on old - reduces growth, survey, delay plant, delay spacing, , IWW not FG.
