Locust Tree New Growth Wilt: Locust Leafminer Outbreak

Wilted, stripped new growth on a thornless locust (likely black locust) is locust leafminer—adults skeletonize leaves, larvae mine inside them.

Lifecycle

• Adults overwinter in bark, emerge at leaf-out.
• Eggs on leaf undersides, overlapping like shingles.
• Larvae mine collectively, then individually. Two generations/year.

Damage vs. Appearance

Outbreaks look dramatic (gray/brown hillsides) but are rarely fatal. Trees refoliate by late summer.

Control (If Desired)

• Systemic insecticide (soil-applied) in late May/early June when mines <1/2 inch.
• Check local nursery for leafminer-specific systemic.
• Often unnecessary—aesthetic only.

Thornless Locust

‘Shademaster’ or ‘Skyline’ honeylocust are thornless cultivars. Black locust usually has thorns.