In large numbers, euonymus scale can devastate evergreen euonymus species. Here’s how to deal with these troublesome pests.
The euonymus scale is a small, sap-feeding insect that feeds on euonymus species. The males are white and easy to spot, as they congregate in groups on the leaves of infested trees. The scaly females are very well camouflaged by their brown colour and favoured home on the tree bark.
They’re most likely to be around between May and August.
Euonymus scale are big enough to see with the naked eye. The white males are oval shaped, measure 1-2mm long and are generally to be found hanging around on the undersides of leaves.
Females look like brownish scales and they’re actually fixed to the spot - usually on tree bark or leaf stems.
When the insects suck sap from the plant, they discolour the foliage, leaving yellow patches. Affected leaves will eventually drop off.
A heavy infestation will weaken the plant, causing severe die-back and loss of vigour.
These insects feed on evergreen euonymus - and they’re particularly keen on Euonymus japonicus.
You’ve got a few alternatives to help control a euonymus scale infestation:
This does sound like a euonymus scale infestation, which particularly affects evergreen species of Euonymus, severely weakening the plant.
The male scales generally appear on the undersides of the leaves, but it is not unusual to see them on the top of the foliage.
You may also notice larger, brownish oyster-shell coloured scales on the stems. These are the females. When scale insects first hatch they are quite mobile and crawl around the plant sucking sap until their hard scaly shells form, when they become firmly fixed to one spot.
Males, females and juveniles may be present at the same time and they are particularly prevalent from late spring to early autumn. Read above to find ways of coping with this invader.
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