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Wax Scale on Japanese Maple: Identifying the White Domes and Timing Your Treatment

Identification

White, dome-shaped spots on branches. Red underneath; "blood" when squashed. This is wax scale. Adult females protect themselves with a waxy coating; red eggs are beneath.

Life Cycle & Critical Window

Eggs hatch in April → tiny "crawlers" emerge.
Crawlers are the only vulnerable, mobile stage.

Control Strategy

Physically remove all visible adults (good first step).
Apply insecticide three times at two-week intervals starting mid-June to kill crawlers.
Check local nursery for scale-specific insecticide.
Avoid horticultural oils on Japanese maple—they can cause phytotoxicity.

Note

Young crawlers are camouflaged on stems; thorough coverage is essential.

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