Seedling Pests

Question 1

SEDA

Answer 1

Stand establishment Decision Aid

Question 2

Hosts and range of IWW

Answer 2

BC interior

moist sites, deep duff, coarse soils (SL)
Larval stage is the damager and found on root collar

Mainly attack Pl. (20% of BC Pl stands attacked with 40-80% trees under attack)

Question 3

What are the IWW preferences

Answer 3

Starts attack at 1m tall (2cm diameter)

Prefers larger stems

Continues onto mature trees

Question 4

Life Cycle of IWW

Answer 4

Larva feed on roots

Larva - 2 years - Adult - 5 years

Adult is flightless

Question 5

Post logging, what happens with IWW

Answer 5

Continue to develop in stump (2-3 years after harvest)

Adults move to surrounding timber

Re-invade when trees reach around 2cm diameter / 1m tall

Advance into stand at about 13m per year.

Question 6

S and S

Answer 6

Bug: white grub (2cm when mature)
adult: dark weevil with grey flecks (long snout)

Tree: reddish foliage when young, Chlorotic when older

stunted growth

Leaning trees (girdling at root collar and on roots. Soil pitch frass combo looks like kitty litter.)

Question 7

Pattern in block created by IWW

Answer 7

Heavy attack on edges of block, slowly spreading inward.

Question 8

IWW damage

Answer 8

Young Tree: girdle at root collar - mortality. 40% infestation and 0-10% mortality. (Young tree can host 1-2 larva but 3 will kill)

Greater damage adjacent to IBM killed stands

Older trees: larger root collar, insect must burrow down further to girdle individual roots.

Some roots girdled, doesn’t kill as easily or as often in older trees (up to 30 larva can live off a tree without killing) Increase susceptibility to IBM.

Question 9

Pre harvest Mgmt

Answer 9

• examine root collars
• if possible, include adjacent Pl types

Site Prep: remove duff (burn, scarily, mound/trench)

Question 10

Mgmt at planting

Answer 10

M-H hazard (delay planting 2-3 years)

20-30 m Donut of non host trees or mix spp / or mix throughout

Plant Higher density (to off set mortality)

If fill planting, No Pl

Question 11

Mgmt at FG JS

Answer 11

In M-H hazard zones delay spacing till 20 or more years when they are resilient enough to survive IWW attack.

Trees with IWW not FG

Question 12

IDA

Answer 12

Black army Cutworms

Question 13

Biology of IDA

Answer 13

Prefer herbs

Lay eggs in ash

L1-L6 (early instars are day feeders, late are night feeders)

Target burn sites (burned in spring, defol. Next spring)
Site burned in Fall (defol. In second spring.)

Question 14

S and S of IDA

Answer 14

• shot holes in foliage after snowmelt (defol. Of herbs and seedlings)
• black larva with 2 sets of racing stripes per side (2 dashed lines)

Question 15

IWW

Answer 15

Insect Weevil Warren

warrens root coolar weevil, one of the main seedling pests