Brewer, B.S., & Oliver, A.D. 1987 Euonymus scale, Unaspis euonymi (Comstock) (Homoptera: Diaspididae): effects of host cultivar age, and location on infestation levels.. Journal of Entomological Science 22: 119-122.

Notes: Infestation frequency was measured on 5 species and varieties of Euonymus; other factors considered such as "protected" environments and age of plants.