Euonymus (Euonymus)-Euonymus scale

Unaspis euonymi

Pest description and damage Euonymus scale females are dark, 0.063 inch long, and mussel-shaped. The males are narrow, elongated, and white. Crawlers are orange. Euonymus scale 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 scale 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 doublesided tape around or near infestations of adult scale to catch the crawler stage. As with aphid, avoid excessive nitrogen fertilizer as this favors population increase.

Management-chemical control

See Table 1 in:

For more information

See "Scale insect" in: