Unaspis euonymi
Pest description and damage Scale insects are small (less than 0.125 inch in length) soft insects that live beneath waxy scales. These insects are often identified by the shape and size of their scales, the description of adult males and females, immature crawler stage, color of eggs, and host plant preferences. The female Euonymus scale insects are dark, 0.063 inch in length, and are under mussel shaped scales. The males are under narrow, elongated, and white scales. Crawlers are orange. Euonymus scales are found on both leaves and stems. Infested leaves develop yellow to white spots from scale feeding, and in severe cases significant defoliation can occur. Euonymus scale infests a wide range of ornamental genera that include Camellia, Buxus, Daphne, Hedera, Ilex, Jasminum, Ligustrum, Lonicera, Pachysandra, and Prunus.
Biology and life history The scales overwinter as fertilized females. In the spring, these females lay eggs and the crawlers emerge from beneath the shells to begin feeding. There may be two to three generations per year.
Management-cultural control
Evergreen euonymus (E. japonica) is extremely susceptible to scale infestations, as is spindle tree (E. europaeus). Euonymus alata (especially 'Compacta') and E. fortunei 'Acutus' are seldom infested. Several other species, including E. kiautschovicus, will tolerate scale feeding. Hand-wipe to help control small infestations, when practical. Prune out heavily infested branches. Apply double-sided tape around or near infestations of adult scales to catch the crawler stage. As with aphid, avoid excessive nitrogen fertilizer as this favors population increase.
Management-chemical control
See Table 1 in:
Chemical Control of Landscape Pests
For more information
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