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Honeylocust plant bug

Diaphnocoris chlorionis

3 host plants

Last updated

Data Coverage 2 of 6 dimensions
Host Plants
GDD Threshold
Peak Activity
Damage Severity
Monitoring
Regional Notes

Honeylocust plant bugs appear on honeylocust foliage in late spring and early summer, feeding by piercing plant tissue and sucking sap. The small bugs (less than 0.25 inch) are brown or darkly colored and congregate on younger leaves. Feeding damage causes yellowing, stippling, and leaf curling; affected foliage may eventually brown and drop. Heavy infestations reduce tree vigor and aesthetic appeal.

Monitor honeylocust trees from late May through July for plant bug presence and early stippling. Remove heavily infested shoots by hand if populations are light. For active populations, apply insecticidal soap or neem oil targeting nymphs and adults. Horticultural oil in late winter targets overwintering adults. Most infestations self-regulate above 80 degrees Fahrenheit.

Quick Reference

Host Plants
3
GDD₃₂ Egg hatch early instar
1,799
Indicator: Blue false indigo first bloom

Regional Season Tracker

GDD₃₂ accumulation across 7 Puget Sound stations · as of Mar 22, 2026
Station GDD₃₂ Current Stage Next To Go
Seattle / UW 1,013 Pre-season Egg hatch early instar 786
Issaquah / East King 1,006 Pre-season Egg hatch early instar 793
Olympia / Tumwater 952 Pre-season Egg hatch early instar 847
Bellingham / Whatcom 948 Pre-season Egg hatch early instar 851
Kent / Auburn 942 Pre-season Egg hatch early instar 857
Sequim / Rain Shadow 924 Pre-season Egg hatch early instar 875
Tacoma / Puyallup 921 Pre-season Egg hatch early instar 878

Source: UMD IPMnet catalog. Sources: UMD: extension.umd.edu. About GDD₃₂ →

Host Plants (3)