Cottonwood leaf beetle is the most damaging insect affecting the production of hybrid poplars, an important source of sustainable forest products and biomass. Current management strategies rely primarily on synthetic pesticides, in part because effective sampling schemes are lacking. Development of such sampling schemes is hindered by the aggregated distribution of these insects, and the absence of any known chemical cues for trapping. We conducted laboratory assays on sources of attraction to cottonwood leaf beetle adults. In olfactometer studies, beetles were strongly attracted to odors arising from other beetles feeding on foliage. There was also significant, but lesser, attraction to unwounded foliage, relative to blank controls. Results on the relative importance of signals arising from insect versus plant cues, and of wounded versus unwounded foliage, are presented. Field assays aimed at incorporating these signals to improve detection and sampling are underway. Based on these results, we propose that original landing by cottonwood leaf beetle adults is mediated by orientation to host plant odors, and that subsequent aggregation is enhanced by chemical cues associated with feeding by conspecifics. This may partially explain patterns of clustered distribution in the field, and likewise be incorporated into sampling schemes needed for integrated pest management.