Greenhouse trials were conducted to determine Hooker's evening primrose transplant tolerance to POST-applied herbicides. Herbicide treatments consisted of glyphosate at 1.68 kg ae ha⁻¹, glufosinate at 0.84 kg ai ha⁻¹, fenoxaprop at 0.10 kg ai ha⁻¹, fluazifop at 0.45 kg ai ha⁻¹ a nonionic surfactant (NIS) at 0.25% v/v, sulfosulfuron at 0.06 kg ai ha⁻¹ NIS at 0.25% v/v, quinclorac at 0.42 kg ae ha⁻¹ methylated seed oil (MSO) at 0.5% v/v, mesotrione at 0.21 kg ai ha⁻¹, and the combination of quinclorac mecoprop dicamba at 0.42 0.21 0.06 kg ae ha⁻¹ MSO at 0.5% v/v. Fluazifop (14%) and fenoxaprop (19%) treatments did not result in any significant phytotoxicity 7 d after treatment (DAT) compared with the nontreated check. Hooker's evening primrose exhibited 26 to 37% phytotoxicity in response to quinclorac, glyphosate, or sulfosulfuron 7 DAT. Phytotoxicity ≥ 50% was observed for mesotrione, glufosinate, and the combination of quinclorac mecoprop dicamba 7 DAT. Phytotoxicity increased for all treatments 28 DAT. Fluazifop (21%) was the only treatment that did not exhibit phytotoxicity symptoms different from the nontreated check 28 DAT. Hooker's evening primrose exhibited 31 to 40% phytotoxicity with applications of fenoxaprop, glyphosate, or glufosinate 28 DAT. Phytotoxicity was ≥ 58% with all other treatments 28 DAT. Fluazifop exhibited similar above-ground (12.4 g) and below-ground (16.4 g) biomass as the nontreated check (10.8 and 14.7 g, respectively) 28 DAT. All other treatments resulted in 1.6 to 5 g of above-ground biomass and 0.8 to 4.3 g of below-ground biomass 28 DAT. Fluazifop (24.3) and fenoxaprop (18.8) applications resulted in a plant growth index (PGI) that was not significantly different from the nontreated check (24.7) 28 DAT. A PGI ≤ 16.2 was observed for all other treatments 28 DAT.

Nomenclature: Dicamba; fenoxaprop; fluazifop; glufosinate; glyphosate; mecoprop; mesotrione; quinclorac; sulfosulfuron; Hooker's evening primrose, Oenothera elata Kunth OEEL

Experimentos de invernadero fueron realizados para determinar la tolerancia de trasplantes de Oenothera elata a herbicidas aplicados POST. Los tratamientos de herbicidas fueron glyphosate a 1.68 kg ae ha⁻¹, glufosinate a 0.84 kg ai ha⁻¹, fenoxaprop a 0.10 kg ai ha⁻¹, fluazifop a 0.45 kg ai ha⁻¹ surfactante no-iónico (NIS) a 0.25% v/v, sulfosulfuron a 0.06 kg ai ha⁻¹ NIS a 0.25% v/v, quinclorac a 0.42 kg ae ha⁻¹ aceite de semilla metilado (MSO) a 0.5% v/v, mesotrione a 0.21 kg ai ha⁻¹, y la combinación de quinclorac mecoprop dicamba a 0.42 0.21 0.06 kg ae ha⁻¹ MSO a 0.5% v/v. Los tratamientos de fluazifop (14%) y fenoxaprop (19%) no resultaron en fitotoxicidad significativa 7 d después del tratamiento (DAT) en comparación con los testigos no tratados. O. elata mostró 26 a 37% de fitotoxicidad en respuesta a quinclorac, glyphosate, o sulfosulfuron 7 DAT. Fitotoxicidad ≥50% se observó con mesotrione, glufosinate, y la combinación de quinclorac mecoprop dicamba 7 DAT. La fitotoxicidad incrementó para todos los tratamientos 28 DAT. Fluazifop (21%) fue el único tratamiento que no mostró síntomas de fitotoxicidad diferentes al testigo no tratado 28 DAT. O. elata mostró 31 a 40% de fitotoxicidad con aplicaciones de fenoxaprop, glyphosate, o glufosinate 28 DAT. La fitotoxicidad fue ≥58% con todos los demás tratamientos 28 DAT. Fluazifop mostró biomasa aérea (12.4 g) y subterránea (16.4 g) similares al testigo no tratado (10.8 y 14.6 g, respectivamente) 28 DAT. Todos los demás tratamientos resultaron en 1.6 a 5 g de biomasa aérea y 0.8 a 4.3 g de bi