What's eating my cercis canadensis 'lavender twist'?

Cercis canadensis 'Lavender Twist' faces the greatest risk from scale insects and borers, with deer browsing young shoots in rural gardens. Caterpillars such as eastern tent caterpillar can defoliate branches in spring. Overall pest pressure is moderate — healthy, well-sited trees recover quickly from most attacks.

Brown, waxy bumps on stems and branches; sticky honeydew coats leaves, often followed by sooty mould; overall vigour declines Apply horticultural oil in late winter before bud break to smother overwintering scales; use insecticidal soap for crawlers in early summer; encourage natural predators such as parasitic wasps

Silken tents in branch forks in spring; colonies strip foliage from entire limbs, leaving only midribs Remove and destroy tents by hand while small; apply Bacillus thuringiensis (Bt) spray to young caterpillars; avoid broad-spectrum insecticides that kill natural enemies

Sawdust-like frass at bark entry holes; dieback of individual branches; oozing wounds at the base or scaffold limbs Keep trees well-watered and vigorous — borer attacks intensify on stressed trees; remove and chip infested wood; no effective chemical cure once larvae are inside

Ragged browsing of low branches and flower buds; bark rubbing by antlers in autumn strips young stems Protect young trees with wire cages or deer-proof fencing; apply deer repellent sprays in autumn and winter; plant in enclosed gardens where possible