The tarnished plant bug, known principally as an agricultural pest, injures young hybrid Populus by feeding on the stems and meristems. Tarnished plant bug eggs, fungi associated with some lesions, and simple mechanical stimuli alone from feeding appeared not to cause lesion formation. Of 20 Populus hybrids tested in a clonal trial, four appeared to be consistently susceptible to lesion injury, with Populus nigra var. betulifolia x trichocarpa the most susceptible. Several clones showed high resistance in the trial but a few were susceptible in other plantings and in host preference tests when caged with tarnished plant bugs. Lesions diminished tenfold on Populus where horseweed, the insect's principal wild host, grew along with susceptible poplars. The tarnished plant bug can be suppressed by ultra-low volume pesticides and cultural manipulation of understory vegetation.
Sapio, Frank J.; Wilson, Louis F.; and Ostry, Michael E.
"A Split-Stem Lesion on Young Hybrid Populus Trees Caused by the Tarnished Plant Bug, Lygus Lineolaris (Hemiptera: [Heteroptera]: Miridae),"
The Great Lakes Entomologist, vol 15
Available at: https://scholar.valpo.edu/tgle/vol15/iss4/3