IDW

Western Spruce Budworm

Source: http://web.unbc.ca/ctl/webcourses/fsty307/defol/wsb_larva.jpg

Hosts & Range (click to expand)

	Fd (B, L, S)
	southern interior (IDF) (Fraser Canyon, Okanagan) and south coast (CDF)
	prefers warm, dry areas 80+% Fd component dense stands
	uneven-aged stands

	Source: http://www.for.gov.bc.ca/tasb/legsregs/fpc/fpcguide/defoliat/fig2.htm
	Note outbreak area vs. distribution

	Source: http://www.na.fs.fed.us/spfo/pubs/fidls/westbw/wbw-map.gif

Life Cycle / Biology (click to expand)

	eggs (150-200) laid in August
	1/2 laid at mating site, other 1/2 somewhere else
	overlapping shingles on underside of needles

	Source: http://www.ext.colostate.edu/pubs/insect/INSIMG/jb003coh.jpg
	larva hatch in late summer look for a shelter, build hibernacula (shelter), molt to L2 OW as L2 emerge in spring (April) and mine into needles or buds (including cone buds) continue feeding as buds emerge ("mined buds" are often toasted) loose webbing around branch tips needles often "planed" and will appear scorched strong preference for new foliage spin down get larger and more voracious as they mature - now in lower portion of crown

	Source: http://web.unbc.ca/ctl/webcourses/fsty307/defol/wsb_larva.jpg
	pupate in July
	adults emerge in August

	Source: http://ext.nrs.wsu.edu/forestryext/foresthealth/notes/images/westernbudworm.jpg
	populations fluctuate with weather

	Source: http://www.pfc.forestry.ca/diseases/nursery/images/full_images/fig110.jpg

Signs & Symptoms (click to expand)

	insect - eggs: fish scales on needle - larva: naked, greenish-brown, 4 white spots per segment, dark head - pupa: naked - adult: grey-brown mottled wings
	tree - branch tips, bud mining, webbing - outer tips looked scorched (burnt), turning grey in fall
	stand - 350-1450m elev.

Damage (click to expand)

	most damaging defoliator of western conifers
	very large outbreaks in BC have occurred (800,000 ha in late 80's, 100,000 ha in 50's) '06 - 775,000 ha '07 - 850,000 ha
	wasteful feeders
	greatest damage/ mortality occurs in intermediate and suppressed trees
	estimated that in the recovery years growth loss is 50-80%

Management (click to expand)

	Annual overview surveys
	Also, in high hazard areas egg mass survey to predict if population building
	bud mining surveys in spring to confirm pop'n level and need for treatment larval surveys later in season to confirm treatment and determine efficacy
	Short Term Action Btk - apply during outbreak for pop'n control spray later instars (usually in build-up or early outbreak) for foliage protection spray early instars
	Long Term Mgmt species management (promote species other than Fd & B) stand structure
	open stand remove under storey under burning