Contents: By Damage and Image
In progress
Contents: Alphabetical

alder flea beetle
aphid management
apple and thorn skeletonizer
apple ermine moth
ash whitefly
azalea bark scale
azalea lace bug
azalea sawfly
Bagrada bug
bark lice
Barypeithes root weevil
Beneficial nematodes
biocontrol of root weevils
birch aphid
black bean aphid
black cherry aphids
black stem borer
bluegum psyllid
Boisduval scale
branch and twig borer
brown marmorated stink bug

bronze birch borer
boxwood leafminer
boxwood psyllid
bulb flies
cabbage whitefly
carnation tortrix
carpet beetle (images)
Calligraph californica

Ceanothus stem gall moth
cereal leaf beetle
cherry ermine moth
chilli thrips
cinnabar moth
clay colored weevil
cottony camellia scale

crane flies
cypress tip moth

dogwood sawfly
Douglas fir sawfly
Douglas fir twig weevil
elm leafminer
European pine sawfly new
European pine shoot moth
European wool carder bee
emerald ash borer
Fall webworm
fir coneworm new
flatheaded cedar borer
ground beetle gallery
Hemerocallis gall midge new
hollyhock weevil
honeylocust plant bug
honeylocust pod gall midge
Heliothis phloxiphaga
holly bud moth
huckleberry root aphids
ground mealybug
Japanese beetle
lady beetle gallery
leaf weevil
light brown apple moth
Linden aphid new
lupine aphid new
Macrosiphum rhamni new
maple aphids
maple tip moth
maple midge
March flies
mountain ash sawfly
Myzocallis sp. on red oak new
Narcissus bulb fly
natural enemies gallery
oak ambrosia beetle
oak slug
oak twig gall wasp
obscure root weevil
Pacific flatheaded borer
peach tree borer
peach twig borer
pear blight beetle
pear psylla
pear leaf-curling midge
pear sawfly
pine needle scale
pine and cone spittlebug
poplar and willow borer
Psyllopsis fraxinicola
rose curculio weevil
rose midge
rove beetle gallery
rose stem girdler
sequoia pitch moth
soldier beetle gallery
snapdragon plume moth new
snakefly gallery
speckled green fruitworm
meadow spittlebug
spotted asparagus beetle
spruce twig aphid
tent caterpillars
viburnum leaf beetle
violet gall midge
western poplar clearwing
western spotted cucumber beetle
white pine weevil
woolly alder aphid new
woolly ash aphid
woolly beech aphid

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Poplar and willow borer

A cryptic weevil as an adult, the damage from the poplar and willow borer, Cryptorhynchus lapathi, is all too obvious. This borer can infest in high numbers in preferred hosts causing high levels of mortality to a stand. Hosts include willow, poplar, alder, and birch. Willow is the preferred host, but hybrid poplar stands can suffer heavy losses. Solomon (1995) reports that balsam poplar and black cottonwood are susceptible while quaking aspen, alder, and birch are rarely attacked.

Both adults and larvae can overwinter in Canada and so are likely to do so in areas west of the Cascades. Summer into fall is the period when adult weevils emerge. The adults are most active in the evening and morning. These weevils can fly but do so rarely as they are sedentary. The newly emerged adults feed on bark of new stem shoots. They mate and can lay eggs shortly after emergence (2 to 10 days). Eggs are laid in crevices of the bark. Females can also chew into the bark, making round holes in which they oviposit one or several eggs and pack with bits of wet sawdust-like wood. There are two peak egg-laying periods: the first in March and April by overwintering adults; and later in July through October from the newly emerged adults (Solomon, 1995)(Garbutt and Harris, 1994). Adults can live two to three years (Garbutt and Harris, 1994). The adult weevils can make a stridulating sound when handled.

Larvae move from overwintering tunnels between the bark and wood, deeper into the stem often into the pith. Pupation occurs in frass plugged galleries, usually from mid-July through September and lasts two to three weeks.

Tree damage includes frass-plugged entrance holes; bark cracking and weeping; round exit holes (often sawdust at base of plant), galling of trunks, larval tunneling which girdles the trees, tree breakage, and secondary pathogens infecting borer wounds. Attacks are most common in stems 2.5 to 10.0 cm in diameter (Solomon, 1995). Galleries are round and often packed with frass.

Garbutt, R.W.; Harris, J.W.E. 1994. Poplar and willow borer. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Forest Pest Leaflet 07, Copublished by the BC Ministry of Forests.

Solomon, J.D. 1995. Guide to insect borers in North American broadleaf trees and shrubs. Agric. Handbk 706. Washington, DC: U.S. Department of Agriculture, Forest Service. 735 p.

Web links:

Poplar and willow borer. 1994. Garbutt, R.W.; Harris, J.W.E. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Forest Pest Leaflet 07, Copublished by the BC Ministry of Forests.

BC Ministry of Forests: Poplar and willow borer, Cryptorhynchus lapathi Nice images.

Frass at entrance hole from poplar and willow borer
poplar and willow borer frass
Photo: Rosetta
Galling damage from poplar and willow borer on willow
poplar and willow borer damage on willow
Photo: Bill Zanze, Portland Parks
Poplar and willow borer damage and resulting breakage
poplar and willow borer damage
Photo: Bill Zanze, Portland Parks
Canker infection at site of borer damage in willow
secondary canker at borer damage site
Photo: Bill Zanze, Portland Parks
Poplar and willow borer tunneling in willow (tentative ID)
poplar and willow borer tunneling
Photo: Bill Zanze, Portland Parks
Poplar and willow borer tunneling in pith (cross section) (tentative ID)
tunnel from poplar and willow borer
Photo: Bill Zanze, Portland Parks
Poplar and willow borer adult (ventral view)
poplar and willow borer adult
Photo: Eryn Cramer
Poplar and willow borer adult
poplar and willow borer adult

Photo: Jim Young
Empty pupal cases in gallery (possibly hymenopteran)
empty pupal cases of poplar and willow borer
Photo: Rosetta
Website editor:
Robin Rosetta

Page last modified 9/5/08


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