What's eating my oxydendrum arboreum?

Sourwood is a largely pest-resistant native tree. Its main threats are leafminers that tunnel through foliage in summer, creating blotchy mines, and scale insects on stems. Deer occasionally browse young plants. Sourwood is susceptible to borer attack when stressed by drought, making adequate moisture the best long-term pest prevention strategy.

Light green or brown blotchy or serpentine mines on leaves in summer; heavily mined leaves may drop early; cosmetic rather than life-threatening No treatment needed for established trees; remove and dispose of fallen leaves in autumn to interrupt life cycles; maintain tree health with adequate water

Waxy or armoured bumps on bark; honeydew and sooty mould; dieback of twigs in heavy infestations Apply horticultural oil at the crawler stage; use dormant oil in late winter; prune and destroy heavily infested branches

D-shaped emergence holes in bark; winding galleries beneath; branch dieback, especially on drought-stressed specimens Water deeply during drought stress; avoid trunk wounds from machinery; remove and destroy infested wood; maintain general tree vigour