Odd white spots on your pachysandra bed likely signal the presence of euonymus scale, a pest that pierces and sucks plant sap. Immediate action may not be necessary unless the infestation becomes significant.

Understanding Euonymus Scale

This pest employs piercing-sucking mouthparts, making insecticide use challenging due to the protective covering adults form. Predominantly, female insects overwinter, laying eggs in late April or May. The larvae or crawlers emerge over two to three weeks. Male insects reside under waxy coatings and mate in spring before the crawlers spread and develop coverings.

Control Measures

First, plan to prune infested pachysandra sections next March to eliminate overwintering females. Dispose of debris in garbage or commercial landscape operations for effective pest eradication. Crawlers are active late May to early June and again in late July through August. Target these periods for pest control using a summer-weight dormant oil.

Taking these steps can reduce the pest population substantially, preserving your pachysandra’s health.

For further advice, contact the Plant Information Service at the Chicago Botanic Garden via email: [email protected].

Tim Johnson, Senior Director of Horticulture at the Chicago Botanic Garden, offers insight into addressing tree problems and managing powdery mildew disease effectively.