Common Insects that Cause Plant Damage in Central Oregon

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

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

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

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

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

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

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

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

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

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)

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

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

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

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

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

Photo: Ken Gray Insect Image Collection

Host: Apple, Pear and Walnut Trees

For more information: Project Happy Apples

Management: See Codling moth in the PNW Insect Management Handbook

Earwigs

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

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

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

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

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

Photo: A. Detweiler, Oregon State University
"D" shaped exit hole in the tree trunk.

Photo: A. Detweiler, Oregon State University
Bronze Birch Borer

Photo: Ken Gray Insect Image Collection

Hosts: White barked birch-Jacque Monti and European White

Management: See Peachtree borer the PNW Insect Management Handbook

Mountain Pine Beetle

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

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