Field experiments were conducted in 2011 through 2013 at the MSU Southern Agricultural Research Center near Huntley, MT, to evaluate the effectiveness of various PRE and POST herbicide programs for kochia control in the absence of a crop. PRE herbicides labeled for corn, grain sorghum, soybean, wheat/barley, and/or in chemical fallow were applied at recommended field-use rates. Acetochlor atrazine, S-metolachlor atrazine mesotrione, and sulfentrazone applied PRE provided ≥91% control of kochia at 12 wk after treatment (WAT). Metribuzin, metribuzin linuron, and pyroxasulfone atrazine PRE provided 82% control at 12 WAT. PRE control with acetochlor flumetsulam clopyralid, pyroxasulfone alone, and saflufenacil 2,4-D was ≤23% at 12 WAT. Paraquat atrazine, paraquat linuron, and paraquat metribuzin controlled kochia ≥98% at 5 WAT. POST control with bromoxynil fluroxypyr, paraquat, tembotrione atrazine, and topramezone atrazine treatments averaged 84% at 5 WAT, and did not differ from glyphosate. Control with POST-applied bromoxynil pyrasulfotole, dicamba, diflufenzopyr dicamba 2,4-D, saflufenacil, saflufenacil 2,4-D, saflufenacil linuron was 67 to 78% at 5 WAT. Because of the presence of kochia resistant to acetolactate synthase-inhibiting herbicides at the test site, cloransulam-methyl was not a viable option for kochia control. In a separate greenhouse study, kochia accessions showed differential response to the POST herbicides (labeled for corn or soybean) tested. Tembotrione atrazine, topramezone atrazine, lactofen, or fomesafen effectively controlled the glyphosate-resistant kochia accession tested. Growers should utilize these effective PRE- or POST-applied herbicide premixes or tank mixtures (multiple modes of action) to control herbicide-resistant kochia accessions in the field. PRE herbicides with 8 wk of soil-residual activity on kochia would be acceptable if crop competition were present; however, a follow-up herbicide application may be needed to obtain season-long kochia control in the absence of crop competition.
Nomenclature: 2,4-D; acetochlor; atrazine; bromoxynil; carfentrazone-ethyl; clopyralid; cloransulam-methyl; dicamba; diflufenzopyr; flumetsulam; flumioxazin; fluroxypyr; fomesafen; glufosinate; glyphosate; isoxaflutole; lactofen; linuron; MCPA; mesotrione; metolachlor; paraquat; pyrasulfotole; pyroxasulfone; saflufenacil; sulfentrazone; tembotrione; thifensulfuron; tribenuron; topramezone; kochia, Kochia scoparia (L.) Schrad.
Entre 2011 y 2013, se realizaron experimentos de campo en el Centro de Investigación Agrícola del Sur de MSU, cerca de Huntley, Montana, para evaluar la efectividad de varios programas de herbicidas PRE y POST para el control de Kochia scoparia en ausencia de un cultivo. Se aplicó herbicidas PRE registrados para maíz, sorgo para grano, soja, trigo/cebada, y/o barbecho químico a las dosis recomendadas para uso en campo. Acetochlor atrazine, S-metolachlor atrazine mesotrione, y sulfentrazone aplicados PRE brindaron ≥91% de control de K. scoparia a 12 semanas después del tratamiento (WAT). Metribuzin, metribuzin linuron, y pyroxasulfone atrazine PRE brindaron 82% de control a 12 WAT. Control PRE con acetochlor flumetsulam clopyralid, pyroxasulfone solo, y saflufenacil 2,4-D fue ≤23% a 12 WAT. Paraquat atrazine, paraquat linuron, y paraquat metribuzin controlaron K. scoparia ≥98% a 5 WAT. Control POST con bromoxynil fluroxypyr, paraquat, tembotrione atrazine, y topramezone atrazine promedió 84% a 5 WAT, y no difirió de glyphosate. El control con aplicaciones POST de bromoxynil pyrasulfotole, dicamba, diflufenzopyr dicamba 2,4-D, saflufenacil, saflufenacil 2,4-D, safluf
