Responses of Four Types of Winter Wheat to Fenoxaprop-p-ethyl

Abstract

Fenoxaprop-p-ethyl is a selective grass herbicide that if registered will provide winter wheat growers with an additional weed control option. Field experiments were established in the fall of 2011, 2012 and 2013 at Ridgetown and Exeter, Ontario, to determine the sensitivity of four market classes of winter wheat [Soft white winter wheat (SWWW), soft red winter wheat (SRWW), hard white winter wheat (HWWW) and hard red winter wheat (HRWW)] to 1X and 2X fenoxaprop-p-ethyl/safener at early-(EPOST) or late-post emergence (LPOST) application timings. Fenoxaprop-p-ethyl/safener applied LPOST at 1X and 2X the manufacturer’s proposed label rate caused 4% and 5% injury 1 week after application (WAA), respectively. The injury observed was transient with 1% injury 2 WAA. Winter wheat height ranged from 91 to 95, 76 to 77, 76 to 79 and 90 to 93 cm while grain yield was 6.2 to 6.4, 6.1 to 7.1, 5.5 to 5.8 and 5.6 to 6.2 t?ha?1 for SWWW, SRWW, HRWW and HRWW, respectively. Exeter sites were not affected by fenoxaprop-p-ethyl/ safener treatment. At Ridgetown and Exeter, no market class-specific response was identified for the cultivars evaluated. Based on this study, fenoxaprop-p-ethyl/safener has the potential to cause only minor and transient injury in winter wheat that will not decrease yield. Furthermore, this research supports the registration of fenoxaprop-p-ethyl/safener for spring POST application in winter wheat in Ontario.