In the absence of contact and visual stimuli, significant numbers of adult striped cucumber beetles,Acalymma vittatum(F.), were caught on veiled sticky cups containing either squash seedlings or blossoms. The role of volatile kairomones in host finding was further demonstrated by the attraction ofA. vittatumadults to a synthetic odor mimic of cucurbit blossoms (a mixture of 1,2,4-trimethoxybenzene, indole, andtrans-cinnamaldehyde [TIC]. From July to late August 1988, TIC-baited traps caught 4–100 times more adult beetles than controls. Although indole was the most active single component of TIC, the slope of the log-dose response curve for the TIC-baited traps was 7 times greater than the slope for the indole-baited traps. Traps baited with the three-component mixture caught twice as many beetles as the theoretical additive response based on the trap catches of the individual components. Several phenylpropanoid attractants forDiabroticaspecies and other squash blossom odor components also were bioassayed in field tests, but none was as active as TIC or indole.