Volatilization of disparlure (cis-7,8-epoxy-2-methyloctadecane) applied in gelatin microcapsules (2%-NCR and 10%-NCR formulations) to 1-ha plots at 500 g/ha was measured intermittently for 2 mo by a micrometeorological technique. The formulations differed in rates and duration of disparlure release. Vapor fluxes initially decreased, later increased with increasing air temperature. Estimated season-long vaporization of the pheromone from the 2 and 10% formulations was only 2.3 and 12.2% of that applied, respectively. Results, which were consistent with laboratory measurements of release rates, showed need for improvement in controlled-release technology.