Insects are divided into categories based on the type of damage they cause including leaf chewers, leafminers, flowers, fruit and seed feeders, sap suckers, trunk and branch borers, gall makers, root, tuber, and bulb feeders. Clicking on the Management link will take you directly to the PNW Insect Management Handbook.
Leaf Chewers
Cabbage Looper
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Cabbage loopers move like an inch worm and chew holes in the leaves
Photo: Utah State University -
Cabbage looper and frass
Photo: University of Minnesota -
Cabbage looper adult
Photo: Keith Naylor, Bugwood.org
Hosts: cabbage, cauliflower, broccoli, kale, other cole crops
Management: See Cabbage and mustard seed-Looper in the PNW Insect Management Handbook
Earwigs
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Close-up of a European earwig
Photo: Ken Gray Image Collection -
Earwig damage on canola
Photo: University of California -
Earwig damage on canola
Photo: Ken Gray Image Collection
Hosts: soft fruits, seedlings, aphids, mites, zinnia, marigolds, dahlias
Management: See Landscape pests-Earwig in PNW Insect Management Handbook
Elm Leaf Beetle
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Larvae and adults feeding
Photo: University of California -
Leaf damage from beetles
Photo: University of California -
Adult beetle
Hosts: Siberian, Rock, English and American Elms. Siberian Elm is common in Central Oregon.
Management: See Elm leaf beetle in the PNW Insect Management Handbook
Fall Webworm
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The larval stage of the fall webworm
Photo: University of Illinois Extension -
Fall webworm and webbing covering a branch on a crabapple
Photo: University of Illinois Extension
Hosts: Several deciduous trees and shrubs
Management: Chemical control generally not recommended. Prune out affected branch. Occurs later in the season, mid to late summer. See Fall webworm in the PNW Insect Management Handbook.
Flea Beetle
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Close-up of Cabbage flea beetle
Photo: Ken Gray Image Collection -
Western flea beetle damage on leaves
Photo: Utah State University
Hosts: Cabbage, broccoli, Brussel sprouts, eggplant, radish, potato, corn, tomato, beans
Management: See Flea beetle in the PNW Insect Management Handbook
Imported Cabbageworm
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Imported cabbageworm larva chew holes in the the leaves
Photo: Utah State University -
Egg on leaf
Photo: Colorado State University -
Imported cabbageworm adult
Photo: David Cappaert, Michigan State University
Hosts: broccoli, cauliflower, cabbage, Brussel sprouts, kohlrabi, mustard greens
Management: See Imported cabbageworm in the PNW Insect Management Handbook
Leafcutter Bee
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Adult leafcutter bee
Photo: Ken Gray Image Collection -
Leafcutter bee damage to a leaf
Photo: Colorado State University
Hosts: Rose, lilac, serviceberry, others
Management: No chemical control recommended as these insect are beneficial pollinators.
Leafrollers
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Adult oblique-banded leafroller
Photo: Washington State University -
Oblique-banded leafroller larva
Photo: Washington State University -
Larval stage rolled up in a leaf
Photo: Utah State University
Hosts: Apples, crabapples, plums, several deciduous trees and shrubs
Management: See Leafroller and leaftier in the PNW Insect Management Handbook
Pear Sawfly
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Adult fly of the pear sawfly
Photo: Ken Gray Image Collection -
Pear sawfly larva feeding on a chokeberry
Photo: A. Detweiler, Oregon State University
Hosts: Cherry, plum, hawthorn, pear, chokeberry, cotoneaster
Management: See Pear sawfly (pear slug) in the PNW Insect Management Handbook
Root Weevil (Black Vine & Strawberry)
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Black Vine Weevil
Photo: Ken Gray Image Collection -
Strawberry Root Weevil
Photo: Ken Gray Image Collection -
Strawberry Root Weevil larva
Photo: Ken Gray Image Collection -
Notched feeding on the leaves is a classic sign of feeding by adult root weevils.
Photo: Utah State University
Hosts: Lilac, rhododendron and many other ornamental plants. Adults feed on the leaves at night.
Management: See Landscape pests-Root weevil in the PNW Insect Management Handbook
Tomato Hornworm
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Tomato hornworm feeding on a tomato plant
Photo: A. Detweiler, Oregon State University -
Feeding damage
Photo: A. Detweiler, Oregon State University -
Adult female hawkmoth
Photo: Shawn Hanrahan, Texas A & M University
Hosts: Tomato, potato
Management: See Tomato hornworm in the PNW Insect Management Handbook
Leafminers
Aspen Leaf Blotch Miner
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The larva mine between the top and bottom layers of the leaf. The larva was pulled out for photo to show it's size.
Photo: A. Detweiler, Oregon State University -
Damage on a leaf
Photo: A. Detweiler, Oregon State University -
Adult moth of the Aspen Leaf Blotch Miner
Photo: David E. Reed, Bugguide.net
Host: Aspen
Management: Leaf miner control (the use of insecticides) is usually not necessary on aspen or poplars. The damage is aesthetic damage and generally does not cause branch dieback or tree failure. Healthy plants can recover from heavy defoliation. Research shows that plants under environmental stress are more susceptible to leaf miner so keep plants in good health. See Landscape pests-Leafminer in the PNW Insect Management Handbook.
Spinach Leafminer
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Leafminer larval stage
Photo: University of Mass Amherst -
Adult leafminer
Photo: USDA -
Damage from leafminers tunneling through the leaves
Photo: Utah State University
Host: Spinach, Swiss chard, beets, other leafy greens
Management: See Spinach-Leafminer in the PNW Insect Management Handbook
Flower, Fruit and Seed Feeders
Codling Moth
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Sting from a codling moth larva tunneling into the fruit.
Photo: A. Detweiler, Oregon State University -
Codling moth larva
Photo: A. Detweiler, Oregon State University -
Codling moth
Host: Apple, Pear and Walnut Trees
For more information: Project Happy Apples
Management: See Codling moth in the PNW Insect Management Handbook
Earwigs
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Close-up of a European earwig
Photo: Ken Gray Image Collection -
Earwig damage on canola
Photo: University of California -
Earwig damage on canola
Photo: Ken Gray Image Collection
Hosts: soft fruits, seedlings, aphids, mites, zinnia, marigolds, dahlias
Management: See Landscape pests-Earwig in PNW Insect Management Handbook
Sap Suckers
Aphids
Hosts: Many trees and shrubs
Management: See Landscape pests-Aphid in the PNW Insect Management Handbook
Leafhopper
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Sharpshooter Leafhopper on a blade of grass
Photo: Colorado State University
Host: Turfgrass-all types. Can be mistaken for whitefly.
Management: See Leafhopper in the PNW Insect Management Handbook
Oystershell Scale
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Oystershell scale covering the trunk of an aspen tree
Photo: A. Detweiler, Oregon State University -
Oystershell scale crawlers below the cover of a now dead scale
Photo: Colorado State University
Hosts: Aspen, ash, cotoneaster, dogwood, maple, willow, lilac
Management: See Scale in the PNW Insect Management Handbook
Pine Needle Scale
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Pine Needle Scales. Note adult scale with an egg appearing from under the cover (pink) and the settled crawler in the upper left.
Photo: Ohio State University -
Pine Needle Scales covering the needles on a pine branch.
Photo: University of Wisconsin
Hosts: Pines and spruce
Management: See Pine needle scale in the PNW Insect Management Handbook
Spider Mites
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Two-spotted spider mite adults and eggs. Spider mites can become a problem on ornamental plants, vegetables and fruit plants during hot, dry weather.
Photo: Ralph Berry, Oregon State University -
Spider mite webbing on tomato plants
Photo: University of Georgia -
Stippling damage from spider mites
Photo: Purdue University Extension Service
Hosts: Spruce, arborvitae, several perennials
Management: See Spider mite in the PNW Insect Management Handbook
Trunk and Branch Borers
Bronze Birch Borer
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Photo: A. Detweiler, Oregon State University -
"D" shaped exit hole in the tree trunk.
Photo: A. Detweiler, Oregon State University -
Bronze Birch Borer
Hosts: White barked birch-Jacque Monti and European White
Management: See Peachtree borer the PNW Insect Management Handbook
Mountain Pine Beetle
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Mature adult mountain pine beetle
Photo: USDA Forest Service -
Pitch tubes along the truck of a pine tree, a sign of mountain pine beetle
Photo: USDA Forest Service
Hosts: Ponderosa, lodge pole, limber, scotch pine trees
Management: See Mountain pine beetle in the PNW Insect Management Handbook
Sequoia Pitch Moth
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Adult Sequoia Pitch Moth
Photo: Ken Gray Image Collection -
Pitch masses on the truck and branches of pine trees.
Photo: A. Detweiler, Oregon State University -
Larval stage that feeds under the pitch mass.
Photo: Ken Gray Image Collection
Hosts: All pine trees
Management: See Pitch moth in the PNW Insect Management Handbook
Gall Makers
Poplar Twiggall Fly
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Gall forming in aspen twigs
Photo: Utah State University -
Adult fly on an aspen leaf
Photo: Whitney Cranshaw, Colorado State University -
Larva of the twiggall fly inside of the branch
Photo: Utah State University
Hosts: Aspen and poplar
Management: See Poplar twiggall fly in the PNW Insect Management Handbook
Root, Tuber and Bulb Feeders
Onion Maggot
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Larva causing damage
Photo: University of California, Davis -
Damage
Photo: Ken Gray Image Collection -
Larva causing damage
Photo: Ken Gray Image Collection -
Adult onion maggot fly
Photo: Ken Gray Image Collection
Hosts: Onion
Management: See Onion seed-maggot in the PNW Insect Management Handbook
Root Weevil (Black Vine & Strawberry)
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Black Vine Weevil
Photo: Ken Gray Image Collection -
Strawberry Root Weevil
Photo: Ken Gray Image Collection -
Strawberry Root Weevil larva
Photo: Ken Gray Image Collection
Hosts: Lilac, rhododendron and many other ornamental plants. The larval stage feeds on the roots of plants.
Management: See Landscape pests-Root weevil in the PNW Insect Management Handbook
