Oilseed cuphea tolerates bromoxynil

Authors: Forcella, Frank; Eberle, Carrie; Gesch, Russell - Russ; Johnson, Jane

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2015
Publication Date: 3/23/2015
Publication URL: http://handle.nal.usda.gov/10113/60554
Citation: Forcella, F., Eberle, C.A., Gesch, R.W., Johnson, J.M. 2015. Oilseed cuphea tolerates bromoxynil. Industrial Crops and Products. 70:201-203.

Interpretive Summary: Oilseed cuphea is a new annual crop for temperate regions. It produces oil in its seeds that is desired by the personal care product industry, especially in high-value shampoos. Unfortunately, growers often are reluctant to test new crops on their farms because weed management strategies for such crops typically are piecemeal at best. Oilseed cuphea suffers from this state of affairs. The crop currently is known to tolerate only a very few herbicides. Additional herbicides would be useful to encourage growers to examine this crop. Herbicides with activity on broadleaf weeds would be especially welcome. Consequently, we tested bromoxynil (the active ingredient in Bronate, Buctril, and other similar herbicides) in both greenhouse and field situations. Oilseed cuphea tolerated POST applications of bromoxynil up to 0.2 lbs. acid-equivalent herbicide per acre (about 1 pint of commercial product per acre), which is a common label rate for this herbicide for traditional crops like corn and wheat. However, the plants had to have reached the 4- to 5-leaf stage of development at the time of application. Earlier applications, or applications at higher rates, could damage cuphea plants or reduce stands. Thus, postemergence applications of bromoxynil at or beyond the 5-leaf stage appear safe for cuphea. This result is useful for growers and seed companies that specialize in new and alternative crops because it eases the management limitations involved with growing a new and unfamiliar crop.

Technical 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 210 g ae ha-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.