Pests
86 pests tracked across Western Washington landscapes, with identification, host plants, and management.
Data collection is ongoing. Profiles deepen as GDD emergence timing, lifecycle details, damage severity, and regional notes are verified from extension research.
GDD Activity Timeline
Updated 2026-05-14Pest emergence mapped to growing degree days (base 32°F). Puget Sound lowlands data with indicator plant correlations.
0 2,113 GDD₃₂ now
6,400
Already active
Woolly apple aphid 945 Leafminer 957 Codling moth 995 Viburnum leaf beetle 1,085 Deutzia first bloom Andromeda Lace Bug 1,415 Hawthorn first bloom Emerald ash borer 1,763 Red horsechestnut first bloom Strawberry crown moth 1,778 Coming up
Bronze birch borer 2,141 Smoketree-Fringetree Leafhopper 2,291 +178 to go Black vine weevil 2,319 American yellowwood first bloom Twospotted spider mite 2,375 American yellowwood full bloom Apple maggot 3,060 +947 to go Japanese Beetle 3,485 Viburnum-Bottlebrush buckeye Spotted Lanternfly 3,700 Bottlebrush buckeye first bloom Peachtree borer 3,872 Butterfly bush-Butterfly weed Pear slug 4,323 +2,210 to go Magnolia Scale 5,765 Regent pagodatree first bloom GDD₃₂ estimates from UMD IPMnet, calibrated to Kent, WA accumulation curve. Indicator plants signal approximate pest activity timing.
Showing 86 pests
Acalitus essigi
Redberry mite
Affects 5 plants
Acrobasis spp.
Leaf crumpler and Mineola moth
Affects 1 plant
Aculus fockeui
Prunus rust mite
Affects 1 plant
Aculus schlechtendali
Apple rust mite
Affects 1 plant
Agrilus anxius
Bronze birch borer
Affects 16 plants
Agrilus cuprescens
Rose stem girdler
Affects 4 plants
Agrilus planipennis
Emerald ash borer
Affects 10 plants
Aphidoidea
Aphid
Affects 447 plants
Archips argyrospila
Fruittree leafroller
Affects 50 plants
Argyresthia cupressella
Cypress tip moth
Affects 26 plants
Boisea rubrolineata
Western boxelder bug
Affects 45 plants
Buprestidae
Flatheaded borers
Affects 1 plant
Byturus unicolor
Raspberry beetle (aka Western raspberry fruitworm)
Affects 0 plants
Cacopsylla pyricola
Pear psylla
Affects 3 plants
Caliroa cerasi
Pear slug
Affects 18 plants
Campylomma verbasci
Campylomma bug
Affects 1 plant
Cercopidae
Spittlebug
Affects 6 plants
Chamaepsila rosae (formerly Psila rosae)
Carrot Rust Fly
Affects 1 plant
Choreutis pariana
Apple-and-thorn skeletonizer
Affects 93 plants
Chrysobothris mali
Pacific flatheaded borer
Affects 36 plants
Cicadellidae
Leafhopper
Affects 50 plants
Cnephasia longana
Omnivorous leaftier
Affects 3 plants
Cornu aspersum
Brown Garden Snail
Affects 1 plant
Cydia pomonella
Codling moth
Affects 49 plants
Dasineura oxycoccana
Blueberry gall midge
Affects 0 plants
Dasineura pyri
Pear leafcurling midge
Affects 0 plants
Delia antiqua
Onion Maggot
Affects 1 plant
Drosophila suzukii
Spotted-wing drosophila
Affects 54 plants
Edwardsiana rosae
Rose leafhopper
Affects 191 plants
Enarmonia formosana
Cherry bark tortrix
Affects 83 plants
Epitrimerus pyri
Pear rust mite
Affects 0 plants
Eriophyes spp.
Blister mite
Affects 1 plant
Eriophyidae
Eriophyid mite
Affects 53 plants
Eriosoma lanigerum
Woolly apple aphid
Affects 1 plant
Forficula auricularia
Earwig
Affects 51 plants
Frankliniella occidentalis
Western flower thrips
Affects 46 plants
Gastropoda
Slug
Affects 8 plants
Grapholita packardi
Cherry fruitworm
Affects 0 plants
Grapholita prunivora
Lesser appleworm
Affects 2 plants
Halyomorpha halys
Brown marmorated stink bug
Affects 85 plants
Lacanobia subjuncta
Lacanobia fruitworm
Affects 1 plant
Lithophane antennata
Green fruitworm
Affects 1 plant
Lycorma delicatula
Spotted Lanternfly
Affects 0 plants
Lygus spp.
Lygus bug and plant bug
Affects 0 plants
Malacosoma spp.
Tent caterpillar
Affects 137 plants
Microtus spp. — primarily Microtus oregoni (creeping vole), M. canicaudus (gray-tailed vole), and M. townsendii (Townsend's vole) in the Pacific Northwest
Voles
Affects 1 plant
Myzus cerasi
Black cherry aphid
Affects 38 plants
Nemocestes incomptus
Woods weevil
Affects 0 plants
Neolecanium cornuparvum
Magnolia Scale
Affects 1 plant
Noctuidae
Cutworm (climbing)
Affects 0 plants
Noctuidae
Cutworms and armyworms
Affects 69 plants
Oecanthus fultoni
Snowy tree cricket
Affects 0 plants
Operophtera brumata
Winter moth
Affects 1 plant
Otiorhynchus spp.
Root weevil
Affects 438 plants
Otiorhynchus sulcatus
Black vine weevil
Affects 1 plant
Parthenolecanium spp.
Lecanium scale
Affects 255 plants
Pegomya rubivora
Cane maggot
Affects 0 plants
Pennisetia marginata
Raspberry crown borer
Affects 10 plants
Pentatomidae
Stink bug
Affects 2 plants
Phyllocoptes gracilis
Dryberry mite
Affects 4 plants
Phyllonorycter elmaella
Western tentiform leafminer
Affects 1 plant
Phytonemus pallidus
Cyclamen mite
Affects 2 plants
Phytoptus pyri
Pearleaf blister mite
Affects 4 plants
Popillia japonica
Japanese Beetle
Affects 0 plants
Pseudococcus maritimus
Grape mealybug
Affects 1 plant
Pyrrhalta viburni
Viburnum leaf beetle
Affects 33 plants
Rhagoletis indifferens
Western cherry fruit fly
Affects 0 plants
Rhagoletis pomonella
Apple maggot
Affects 45 plants
Schizura concinna
Redhumped caterpillar
Affects 16 plants
Scolytus rugulosus
Shothole borer
Affects 39 plants
Scutigerella immaculata
Garden symphylan
Affects 1 plant
Spilonota ocellana
Eyespotted bud moth
Affects 2 plants
Stephanitis takeyai
Andromeda Lace Bug
Affects 2 plants
Symphyta
Sawfly
Affects 16 plants
Synanthedon bibionipennis
Strawberry crown moth
Affects 1 plant
Synanthedon exitiosa
Peachtree borer
Affects 38 plants
Syneta albida
Syneta beetle
Affects 1 plant
Tetranychidae
Spider mite
Affects 337 plants
Tetranychus urticae
Twospotted spider mite
Affects 1 plant
Thysanoptera
Thrips
Affects 25 plants
Tortricidae
Leafroller
Affects 95 plants
Various
Insect contaminants at harvest
Affects 0 plants
Various (Agromyzidae, Gracillariidae, Tenthredinidae)
Leafminer
Affects 42 plants
Various (Lepidoptera)
Looper
Affects 0 plants
Vespula spp.
Yellowjacket
Affects 0 plants
Yponomeuta malinellus
Apple ermine moth
Affects 14 plants