Camelina is an emerging oilseed crop suitable for biofuel production in dryland cropping systems of the northwestern United States. Currently, camelina growers have limited herbicide options available for weed control. Tolerance of camelina to PRE applications of quinclorac, S-metolachlor, dimethenamid-P, pendimethalin, and pyroxasulfone was evaluated at two locations (Kalispell in 2009 and 2010, and Huntley in 2010 and 2011) in Montana. Susceptibility to each herbicide was determined at three different rates. Quinclorac applied PRE at 280 to 840 g ai ha⁻¹ did not significantly injure camelina, and had no negative effect on plant density, biomass, flowering, and yield at either location. S-Metolachlor at 1,060 to 2,140 g ai ha⁻¹ caused less than 20% injury to camelina, with no reductions in plant density, biomass, and yield compared with the nontreated check. Dimethenamid-P applied at 630 g ai ha⁻¹ did not affect camelina density, biomass, flowering, and yield; however, at the 1,260 g ha⁻¹ rate, injury was as high as 60% (in the coarse-textured Kalispell soil), and plant density and yield were reduced as much as 50 and 31%, respectively, in addition to delayed flowering. Despite causing some visual injury to camelina, crop yield was not reduced by pendimethalin at the 1,060 or 2,130 g ai ha⁻¹ rate. Pyroxasulfone caused significant crop injury, stand loss, and yield reductions, and thus does not appear to be a viable option for weed control in camelina. Camelina plants that exhibited early-season injury showed robust growth and compensatory abilities, with lack of significant effect of herbicides on late-season plant height and biomass at least in one of the two locations. On the baseis of this research, quinclorac was the safest of all herbicides tested in camelina. Dimethenamid-P, S-metolachlor, and pendimethalin also may have an acceptable level of crop safety at lower use rates for possible registration in camelina.

Nomenclature: Quinclorac; S-metolachlor; dimethenamid-P; pendimethalin; pyroxasulfone; camelina, Camelina sativa (L.) Crtz.

Camelina es un cultivo oleaginoso nuevo que es adecuado para la producción de biocombustibles en sistemas de producción en zonas secas del noroeste de los Estados Unidos. Actualmente, los productores de camelina tiene opciones limitadas de herbicidas para el control de malezas. Se evaluó la tolerancia de camelina a aplicaciones PRE de quinclorac, S-metolachlor, dimethenamid-P, pendimethalin, y pyroxasulfone en dos localidades (Kalispell en 2009 y 2010, y Huntley en 2010 y 2011) en Montana. La susceptibilidad a cada herbicidas se determinó con tres dosis diferentes. Quinclorac aplicado PRE de 280 a 840 g ai ha⁻¹ no dañó la camelina significativamente, y no tuvo un efecto negativo en la densidad de plantas, la biomasa, la floración, y el rendimiento en ninguna de las localidades. S-metolachlor aplicado con dosis de 1,060 a 2,140 g ai ha⁻¹ causó menos de 20% de daño a camelina, y no redujo la densidad de plantas, la biomasa, o el rendimiento, al compararse con el testigo no tratado. Dimethenamid-P aplicado a 630 g ai ha⁻¹ no afectó la densidad de la camelina, la biomasa, la floración o el rendimiento. Sin embargo, a 1,260 g ha⁻¹, el daño alcanzó 60% (en suelos Kalispell de textura gruesa), y la densidad de plantas y el rendimiento fueron reducidos hasta 50 y 31%, respectivamente, además de que se observó un retraso en la floración. A pesar de que causó daño visual a la camelina, el rendimiento del cultivo no se redujo con aplicaciones de pendimethalin a dosis de 1,060 ó 2,130 g ai ha⁻¹. Pyroxasulfone causó daño significativo al cultivo, pérdida de plantas, y reducciones en el rendimiento, por lo que parece que no es una opción viable para el control de malezas en came