Wax Scale on Japanese Maple: Identification and Control

A Japanese maple had what looked like small mushrooms on its branches—identified as wax scale (Ceroplastes spp.). Adult females cover themselves in white wax while sucking sap. Red eggs are laid beneath the wax. Physical removal of adults is a good first step.

Control hinges on timing: spray horticultural oil in late winter (February) on a warm day to smother some overwintering nymphs. The critical window is April, when crawlers hatch. Apply carbaryl (Sevin) three times at two-week intervals starting mid-April to target the vulnerable mobile stage.

Management Plan:

• Scrub off visible adults with a soft brush.
• Dormant oil spray in February.
• Carbaryl sprays in April (3 applications, 2 weeks apart).
• Monitor for reinfestation.

Scale insects are persistent—consistency wins.