The proboscis extension response technique was used to evaluate the feeding response of male bollworms, Helicoverpa zea (Boddie), captured in sex pheromone traps to various sugars and other plant products. Such information is essential in research on the development of technology to control H. zea adults using feeding attractants/stimulants. Males evaluated at night in an outdoor insectary under red light had a higher and more uniform response to sucrose and fructose but not glucose than males evaluated during the day under laboratory conditions. The response in decreasing order for sugars eliciting the highest response was fucose, sucrose, fructose and glucose. There was little or no response to sorbose, ribose, maltose, raffinose, turanose, rhamnose, galactose and melezitose at concentrations up to 1.0 M. Males responded similarly to sucrose and raw sugar relative to percent dissolved solids. Males also responded similarly to different concentrations of dissolved solids of nectar from the night-blooming plant species, Gaura suffulta, G. longiflora, and G. drummondii; the response was very similar to that obtained for sucrose. There was little or no response to undiluted corn steep liquor and the commercial phagostimulants Mo-Bait®, Gusto®, Konsume® and Coax®, but there was a high response to undiluted G. suffulta nectar and honey. Adult food containing honey, beer, ascorbic acid and L-cysteine hydrochloride in deionized water elicited an intermediate response. Contact with blooms of several fall-blooming plants and honeydew on ergot-infected dallisgrass seedheads induced relatively high response. This result suggests that the proboscis extension response bioassay could be useful for identifying adult food plants.