Growth chamber studies were conducted to investigate the effect of temperature, cultivar, and leaf wax content on the response of broccoli and collard to oxyfluorfen. Broccoli cultivars grown under cool temperatures (15/10 C) were more susceptible to preemergence (PRE) application of oxyfluorfen, and broccoli and collard cultivars grown at cool temperatures were more susceptible to postemergence (POST) application of oxyfluorfen than cultivars grown under warm temperatures (25/20 C). Differences between the tolerant cultivar ‘Pinnacle’ and the susceptible cultivar ‘Packman’ in response to PRE oxyfluorfen application were more distinct at warm temperatures than at cool temperatures. Although the broccoli and collard cultivars used in the POST study varied in leaf wax content, differences in wax content did not appear to be as important as other genetic factors in the differential response to POST oxyfluorfen application between cultivars.
