What's eating my gleditsia triacanthos f. inermis?

Thornless honey locust is susceptible to the same pests as the species: mimosa webworm webs and strips leaflets in late summer, honey locust plant bug distorts spring growth, and gall midges curl leaflets. Canker diseases can follow drought stress. Mimosa webworm is the most visible and commonly reported pest problem.

Silky webs enclosing brown, papery leaflets; heavy infestations cause general browning by August Cut out and bag web masses; spray with Bt or spinosad while larvae are young; repeat applications may be needed for a second generation

Yellow stippling and curling of leaflets; plant appears drought-stressed in spring Insecticidal soap targeting nymphs in May; damage rarely requires treatment on established trees

Leaflets folded and galled around tiny larvae; infested shoot tips fail to expand Remove infested shoot tips; apply systemic insecticide at bud break for serious annual infestations