Differential Susceptibility of Six Euonymus Species and Cultivars to Euonymus Scale, Unaspis euonymi (Comstock)

The susceptibility of Euonymus species and cultivars to infestation by euonymus scale was studied in both field-grown and container plants. Significantly lower levels of euonymus scale were observed on Euonymus kiautschovicus ‘Manhattan’, E. japonicus, and E. fortunei in the field studies. In contrast, E. japonicus ‘Albo-marginatus’ and E. japonicus ‘Microphyllus’ had the highest infestation levels, indicating greatersusceptibility to euonymus scale. In container studies, E. japonicus ‘Albo-marginatus’ was the most susceptible of the species and cultivars; however, none of the remaining 5 differed significantly from one another

Distribution of Natural Enemies of Euonymus Scale, Unaspis euonymi (Comstock), in Virginia

The colonization of Chilocorus kuwanae (Silvestri) (Coleoptera: Coccinellidae) and Cybocephalus nipponicus (Endrody-Younga) (Coleoptera: Nitidulidae), introduced predators of euonymus scale, Unaspis euonymi L., was evaluated on evergreen euonymus scale, Euonymus japonica L., by regional and statewide surveying. This study determined the statewide distribution of the native parasites of euonymus scale, Aspidiotiphagus spp. and Encarsia spp. (Hymenoptera: Aphelinidae). Highest recovery incidences were from 18 of the 41 survey sites on 25 May. The survey established the survival and dispersal of C. kuwanae in metropolitan areas of Virginia with recoveries in 8 of the 12 cities.