Description and Biology
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 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.
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.
- Armored Scale Insect Pests of Trees and Shrubs (Hemiptera: Diaspididae). Miller, D. R. and J. A. Davidson. 2005. 442 pp. Cornell University Press.
- Armored Scale Identification and Management on Ornamental Plants. Frank, S. 2019 (revised). NC State Extension Publications, Entomology Insect Notes.
- Florida Armored Scale Insects. Dekle, G. W. 1965. Arthropods of Florida and Neighboring Land Areas, Vol 3. 265 pp.
- Horticultural Oils for Ornamental Plants. Frank, S. et al. 2018. Entomology Insect Notes, NC State Extension Publications.
- NC State Extension Plant Pathology Publications
- NC State Horticultural Science Publications
- North Carolina Agricultural Chemicals Manual
For assistance with a specific problem, contact your local Cooperative Extension Center.
This factsheet has not been peer reviewed.
Publication date: Nov. 16, 2021
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your local N.C. Cooperative Extension county center.
N.C. Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status.