What's eating my emerald gaiety euonymus?

Emerald Gaiety Euonymus is heavily targeted by euonymus scale, its most serious pest, which can kill branches or whole plants if untreated. Euonymus caterpillar and aphids are secondary threats. Crown-and-root rot from Phytophthora can be confused with pest damage. In the UK, the box tree moth may occasionally wander onto adjacent plantings.

White elongated male scales and dark brown female scales encrust stems and leaves; yellow spotting, branch dieback, plant death in severe infestations Apply horticultural oil in late winter and again in late spring when crawlers are active; prune out heavily infested stems; systemic insecticide for severe cases

Silk webbing tents over foliage; larvae strip plants of all leaves, leaving only silk and frass Remove silk tents and larvae by hand while small; apply Bacillus thuringiensis (Bt) spray to young caterpillars; prune out infested shoots

Distorted, sticky new growth; honeydew drips; sooty mold blackens foliage below colonies Spray colonies off with water; apply insecticidal soap or neem oil; repeat weekly until controlled

Notched leaf margins from adult feeding; root damage from larvae causing sudden wilting and plant death Apply beneficial nematodes (Steinernema kraussei) to soil in late summer; use sticky barriers on stems against adults