NC State Extension Publications

Description and Biology

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Spinose scales, Oceanaspidiotus spinosus are also called spined scales and avocado scales and are armored scale insects. Female armor is circular, light brown to grayish, opaque, with central shed skins and about 1/16 inch in diameter. Male armor is smaller and elongate with shed skins off center. When her armor is lifted, the body of the female is yellow. The biology of this species has not been published, but its general life history must be similar to that of other armored scale insects. Tiny, gnat-like males with two wings and four eyes must emerge from their armor to mate with females through a slit at the edge of her armor. Some populations lack males, which means females can lay fertile eggs without mating. Females must lay eggs under their armor, bu numbers of eggs per female and times required for development are not known. These scales are found on bark and upper and lower surfaces of leaves. Although it infests numerous host plants, spinose scales are not considered to be of economic importance.

Spinose scales are light brown to dirty white

Spinose scales are light brown to dirty white.

Host Plants

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Spinose scales have been recorded from apple, avocado and bays, azalea, blackberry, blueberry, camellias, dogwood, English ivy, fig, haw, hollies, magnolia, maple, oleander, palms (14 species), privet, raspberry, red pepper, rose, styrax, viburnum, wax myrtle, yew, yucca, and many other species in 62 genera of host plants.

Residential Recommendations

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If spinose scales become so abundant that insecticide applications are wanted, dormant oil applications can be made in winter to kill scales on trunks and branches. During the growing season target the crawler stage with horticultural oil, systemic insecticide, insect growth regulator, or other insecticide labeled specifically for armored scales.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

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Publication date: Nov. 16, 2021

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