Ladybugs for euonymus scale
Chilocorus kuwanae, a black lady beetle with two red spots, was imported by the USDA and released in many states; it eats armoured scales including euonymus scale, and Penn State notes its introduction in the eastern US for that pest. UC IPM says each larva eats more than 100 scales and it is now established across much of the US. Conserve it by using horticultural oil on crawlers instead of broad-spectrum insecticides. Bought convergent lady beetles are aphid feeders and are the wrong insect for scale.
Before you act
Everyone's first idea for aphids, and the one beneficial where buying is usually the wrong move. The ladybugs sold by the tub are convergent lady beetles collected from the wild, and UC IPM says most fly away within a day or two of release, even when aphids are plentiful. The larvae do much of the eating, and they turn up on their own wherever there are aphids. How to recognise it, what it is confused with and how to keep it around are on the full Ladybugs profile.
Other controls for euonymus scale
- Rhyzobius lophanthaePredatory lady beetle · 2–6 per 10 ft² (1 m²) or 2–5 per infested plant, every 1–2 weeks; 10–40 per tree