Forest Pests Characteristics

Cooley spruce gall adelgid

Complicated lifestyles; parthenogenic on Douglas fir and sexual reproduction on spruce

Live two years

Mealy bugs and Armoured Scales

Parthenogenic and sexual reproduction

Spongy moth

Host: generalist on deciduous trees and shrubs. Polyphagous

Damaging stage: larvae

Satin moths

Host: Aspen, poplar, cottonwood and willow

Damaging stage: larvae

Large aspen tortrix

Host: Aspen, balsam poplar and willow

Damaging stage: larvae

Overwinter: 2nd instar larvae under dead bark or moss with a hibernaculum

Damage: defoliator; larvae gather fully expanded leaves and fold them with silk threads to feed and pupate. Early season

Eggs: upper surface of leaves in clusters

Eastern spruce budworm

Host: Balsam fir, spruce, hemlock, larch

Damaging stage: larvae

Overwinter: 2nd instar larvae

Damage: needle, male flower, cone and bud.

Larvae gather two or three shoots with silk webs to form a

tunnel.

Eggs: in clusters on the needles

Forest tent caterpillar

Host: generalist on deciduous trees; most important defoliator of aspen in Canada

Damaging stage: larvae

Overwintering stage: 1st instar larvae IN egg

Bonze birch borer

Host: birch

Overwinter: pupae: overwinters in sapwood. Resumes feeding in spring D-shaped hole emergence

Life cycle: 2 years

Eggs: singly in bark crevices

Damage: Larvae forms zigzag tunnel in the inner-bark (phloem) and surface of sapwood (xylem).

Emerald ash borer

Adults: feed on foliage

Host: ash

Overwinter: larvae: in sapwood, Resumes feeding in spring D-shaped hole emergence

Life cycle: 2 years

Eggs: singly in bark crevices

Damage: Larvae forms S-shape tunnel in the inner-bark (phloem) and surface of sapwood (xylem).

White-spotted sawyer beetle

Host: spruce, pine, firs, tamarack

Overwinter: Larvae in heartwood. Resumes feeding in spring; Circular shape hole emergence

Life cycle: 2 years

Eggs: singly in bark crevices

Damage: Larvae forms U-shape tunnel in the inner-bark (phloem) and sapwood (xylem)

Warren’s Root collar weevil

Host: white spruce, jack pine and lodgepole pine

Overwinter: pupae and larvae

Life cycle: 2 years

Eggs: singly in bark crevices at trunk base

Damage: Larvae tunnels beneath the bark of the roots and root collar. On mature trees causes root rot or other fungi/bacterial diseases and stunted growth. On young trees causes windfall

white pine weevil

Host: pine and spruce

Damaging stage: larvae; feed from the cambium of

the twig, pupate in cells in the xylem of larger stems

Overwinter: adults in duff

Life cycle: 1 year

Eggs: feeding punctures in terminals

Mountain pine beetle

Host: lodgepole pine, jack pine

Damaging stage: larvae

Life cycle: 1 year

Overwinter: mainly larvae

Pine engraver

Host: pine, occasionally spruce

Damaging stage: larvae

Life cycle: 1 year

Overwinter: adult in duff

Smaller European elm bark beetle

Host: Elm, vectors Dutch Elm disease

Damaging stage: larvae

Life cycle: 1 year

Overwinter: larvae

Balsam-fir sawfly

Host: Balsam fir, Douglas fir and white spruce

Damaging stage: larvae, Damage: needles

Life cycle: 1 year

Overwinter: eggs

Elm sawfly

Host: Elm and willow

Damaging stage: larvae

Damage: leaves

Life cycle: 1 year

Overwinter: prepupae in duff

Banded horntail

Host: Spruce

Damaging stage: larvae

Damage: sapwood

Life cycle: 1 year

Overwinter: eggs in sapwood

Larch sawfly

Host: Larch

Damaging stage: larvae, Damage: needles

Life cycle: 1 year

Overwinter: larvae in moss or duff

Birch leaf miner sawfly

Host: birch

Damaging stage: larvae, damage: leaf mining damage on birch leaves

Not a large pest in Edmonton any longer, controlled by the parasitoid wasp Lathrolestes luteolator

Willow pinecone gall midge

Host: willow

Damaging stage: larvae, Damage: developing tip

Life cycle: 1 year

Overwinter: 3rd instar larvae in gall

Pine engraver galleries:

Male beetles construct nuptial chambers to accommodate several females

Females construct galleries in the phloem from the nuptial

chamber where they lay eggs

Larvae tunnel feeding galleries at right angles from the egg gallery and usually run in any direction.

Mountain pine beetle galleries:

Female beetles infest trees first and form long vertical galleries

in the inner bark.

Females produce an aggregation pheromone to attract male and female

Larvae bore lateral galleries and overwinter, Larvae resume feeding in the spring and pupate in a cell

Small European elm bark beetle galleries

Adults feed on crotches of small twigs

Tunnel into the cambium and lay eggs

Larval galleries fan out at right angles from the egg gallery