Contents: By Damage and Image
(In progress)
Contents: Alphabetical
alder flea beetle
aphid management
apple and thorn skeletonizer
apple ermine moth
ash whitefly new
azalea bark scale
azalea lace bug Updated
bark lice
Barypeithes root weevil
Beneficial nematodes
biocontrol of root weevils
birch aphid
black stem borer
bluegum psyllid
branch and twig borer
brown marmorated stink bug

bronze birch borer
boxwood leafminer
boxwood psyllid
bulb flies
carpet beetle New
Calligraph californica

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

dogwood sawfly
Douglas fir sawfly
Douglas fir twig weevil
elm leafminer
European pine shoot moth
European shot-hole borer Updated
European wool carder bee
emerald ash borer
Fall webworm
flatheaded cedar borer
hollyhock weevil
honeylocust plant bug
honeylocust pod gall midge
Heliothis phloxiphaga
holly bud moth
huckleberry root aphids
ground mealybug
lady beetle gallery
leaf weevil
light brown apple moth
maple tip moth
maple midge
March flies
mountain ash sawfly
spruce aphid on spruce
oak ambrosia beetle
oak slug
obscure root weevil
Pacific flatheaded borer
peach tree borer
peach twig borer
pear psylla
pear leaf-curling midge
pear sawfly New
pine needle scale
poplar and willow borer
rose curculio weevil
rose midge
sequoia pitch moth
speckled green fruitworm
tent caterpillars
viburnum leaf beetle
violet gall midge
western poplar clearwing
western spotted cucumber beetle
white pine weevil
woolly ash aphid

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Pacific flatheaded borer

Damage from the Pacific flatheaded borer, Chrysobothris mali, often can be seen in late August and September in shade tree production. The following images were taken during August of flatheaded borer damage and larvae on cherry and plum trees. Adult borers emerge from late May-June and are ported to fly for about one month.

Generally insecticides are not recommended for this pest in nursery production. Rather growers rogue out and burn thoroughly infested material. Try to determine the cause of stress to the trees. Drought stress, sunburn, root anoxia are some of the underlying factors making trees susceptible to flatheaded borer damage.


Oregon State University Pacific flatheaded borer fact sheet

Forest Pests of North America: Pacific flatheaded borer

Sawdust or frass from wound on cherry
borer frass
Photo: Rosetta
Frass and weeping on plum
borer frass on plum
Photo: Rosetta
More subtle frass evidence on plum
frass on plum
Photo: Rosetta
Weeping wound on cherry
weeping damage
Photo: Rosetta
Pacific flatheaded borer larva
flatheaded borer larva
Photo: Rosetta
Pacific flatheaded borer adult
Pacific flatheaded borer adult
Photo: Ken Gray
Website editor:
Robin Rosetta

Page last modified 6/7/06


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