Scale insect
Coccoidea
73 host plants
Last updated
Data Coverage 2 of 6 dimensions
Scale insects appear as small, brown, rounded lumps on plant stems, around leaf joints, and undersides of leaves throughout Western Washington; colors range from brown to white, tan, or orange. Heavy infestations result in poor growth, reduced vigor, yellowed leaves, and eventual decline in heavily infested hosts. Black sooty mold growth indicates honeydew excretion.
For light infestations, remove scales with a soft brush dipped in soapy water. Horticultural oil with thorough coverage suppresses crawlers; repeat every 6-7 days for control. Target immatures rather than armored adults. Maintain vigor to boost natural predators.
Quick Reference
Host Plants
73
Peak Activity
April through June for most species; some armored scales produce a second gen...
Host Plants (73)
Acer crataegifolium Hawthorn, Maple Buxus bodinieri Bodinier's Boxwood Buxus microphylla Buxus microphylla Buxus microphylla var. koreana Korean Littleleaf Boxwood Buxus sempervirens Common Boxwood, Common Box European Box Crataegus ambigua Russian Hawthorn Crataegus autumn Crataegus autumn Crataegus columbiana Columbia Hawthorn Crataegus crus Crataegus crus Crataegus douglasii Black Hawthorn Crataegus germanica Medlar Crataegus laevigata English Hawthorn Crataegus lavallei Lavalle Hawthorn, Carrierei Hawthorn Crataegus monogyna Singleseed Hawthorn, Common Hawthorn, English Hawthorn Crataegus phaenopyrum Washington Hawthorn Crataegus punctata Dotted Hawthorn, Flat-topped Hawthorn Crataegus viridis Green Hawthorn,Southern Hawthorn Fraxinus americana White Ash, American Ash Fraxinus anomala Singleleaf Ash, Dwarf Ash Fraxinus excelsior Euopean Ash, Common Ash Fraxinus latifolia Oregon Ash Fraxinus ornus Flowering Ash Fraxinus oxycarpa Fraxinus oxycarpa Fraxinus pennsylvanica Green Ash Fraxinus quadrangulata Blue Ash Fraxinus sieboldiana Siebold Ash, Japanese Flowering Ash, Chinese Flowering Ash Photinia ×fraseri Red Tip Photinia Photinia davidiana Chinese Stranvaesia Photinia davidiana var. undulata Wavy-leafed Chinese Stranvaesia Photinia glabra Japanese Photinia Photinia serratifolia Chinese Photinia Taiwanese Photinia Photinia villosa Oriental Photinia Prunus americana Wild Plum American (Red) Plum August Plum, Goose Plum Prunus armeniaca Apricot Prunus avium Sweet Cherry Prunus besseyi Sand Cherry, Western Sand Cherry Prunus blireiana Blireiana Plum Prunus caroliniana Carolina Cherrylaurel American Cherrylaurel Prunus cascade Prunus cascade Prunus cerasifera Cherry, Plum Prunus cistena Purpleleaf Sandcherry Redleaf Sandcherry Cistena Sandcherry Cistena Plum Prunus dream Prunus dream Prunus emarginata Bitter Cherry, Wild Cherry, Quinine Cherry Prunus first Prunus first Prunus fruticosa Steppe Cherry, European Dwarf Ground Cherry, Mongolian Cherry Prunus glandulosa Dwarf Flowering Almond Prunus ilicifolia Hollyleaf Cherry, Holly-leaved Cherry Prunus laurocerasus Cherry, Laurel Prunus lusitanica Portugal Laurel Prunus maackii Amur Chokecherry Amur Cherry, Manchurian Cherry Prunus mume Japanese Apricotc Japanese Flowering Apricot Japanese Flowering Plum Prunus newport Newport Flowering Plum Prunus okame Okame Flowering Cherry Prunus padus European Birdcherry Common Birdcherry Prunus prostrata Rock Cherry, Mountain Cherry Prunus sargentii Sargent Cherry, Sargent's Cherry Prunus serotina Black Cherry, Rum Cherry Prunus serrula Birchbark Cherry, Paperbark Cherry, Tibetan Cherry Prunus serrulata Japanese Flowering Cherry Prunus snow Prunus snow Prunus subcordata Klamath Plum, Sierra Plum, Pacific Plum Prunus subhirtella Higan Cherry Prunus subhirtella var. autumnalis Autumn Flowering Higan Cherry Prunus tai Prunus tai Prunus virginiana Prunus virginiana Prunus virginiana var. demissa Western Chokecherry Prunus virginiana var. virginiana Common Chokecherry, Eastern Chokecherry Prunus yedoensis Yoshino Cherry, Somei-yoshino Cherry, Tokyo Cherry Rhaphiolepis indica Indian Hawthorn Rhaphiolepis umbellata Yeddo Rhaphiolepis Yeddo Hawthorn Thuja occidentalis Eastern Arborvitae, American Arborvitae Eastern White-cedar Thuja orientalis Chinese Arborvitae, Oriental Arborvitae Thuja plicata Western Redcedar