University of Kentucky College of Agriculture

Scale Insects in Kentucky

University of Kentucky College of Agriculture


Scale Host Appearance Crawlers Active in Kentucky
Cottony Maple Scale maples, other woody plants flat, oval, brown, 1/8 inch long with large white cottony egg sac protruding from under body June and July 
Euonymus Scale Euonymus spp., Pachysandra, Bittersweet females: dark brown or gray, 1/16 inch long, resemble oystershell scales, pear-shaped; males: smaller, narrow, white. First brood: late May; Second and third broods: late July to early September
Juniper Scale Juniper, Arborvitae female: circular, flat, dirty white, 1/20 inch, yellow exuviae off-center (looks like a fried egg); males:smaller, narrow, exuviae located at end of shell mid-May
Lecanium Scales Arborvitae, Sweetgum, Zelkova, other hosts mostly hemispherical or turtle-shaped, brown, 1/8 to 1/6 inch. varies with species
Magnolia Scale Magnolia, Tuliptree broadly oval, convex, 1/2 inch long early September
Obscure Scale Pin Oaks, Hickory, Walnut roughly circular, flat, 1/8 inch, exuviae form a central spot surrounded by a gray ring June through August; late July is best time for a single treatment
Oystershell Scale Lilac, Maple, Willow, other hosts oyster-shaped, gray, 1/8 inch, exuviae accumulated at narrow end early May when hawthorn blooms
Taxus Mealybug Taxus, (apple, cedar, linden, maple) adult mealybug is approx. 8 mm long, they cluster in crotches of twigs and branches; white-gray in color latter half of May, summer
Tuliptree Scale Tuliptree, Walnut, other plants hemispherical, 1/3 inch late August
Walnut Scale wide variety of deciduous trees and shrubs, rarely on conifers nearly circular, flat, gray with a reddish-brown spot mid-June, late August to early September


Revised: 7/96


CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.




Images: University of Kentucky Entomology