Oilseed cuphea tolerates bromoxynil

Abstract

Weed management is a critical feature of all crop production, but especially for new and alternative crops with which most growers have little experience. Oilseed cuphea is a new annual crop for temperate regions and, at present, it is known to tolerate only a narrow spectrum of herbicides. Additional herbicides would be useful to encourage growers to examine this crop on their farms. Of particular importance are herbicides with broad activity against dicotyledonous weeds. Accordingly, cuphea tolerance to bromoxynil was tested in both greenhouse and field settings. Oilseed cuphea tolerated postemergence applications of bromoxynil up to 210gaeha−1, which is a common label rate for this herbicide for traditional crops, but only if the plants had reached the 4- to 5-leaf stage of development at the time of application. Earlier applications, or applications at higher rates, could damage plants or reduce stands. Thus, postemergence applications of bromoxynil at or beyond the 5-leaf stage appear safe for cuphea. This result broadens the spectrum of potentially competing weed species that can be managed effectively if they co-occur with oilseed cuphea.