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Early-Season Weed Control Using Herbicides with Adjuvants in Direct-Seeded Onion

  • James R. Loken (a1) and Harlene M. Hatterman-Valenti (a1)


Early-season weed competition may cause substantial yield losses in onion. Oxyfluorfen and bromoxynil are POST herbicide options for weed control once onion has developed two leaves, which often takes 4 to 6 wk. Multiple applications of oxyfluorfen at 35 and 18 g ai ha−1 and bromoxynil at 35 and 18 g ae ha−1 with adjuvants were evaluated for onion safety and weed control under controlled greenhouse conditions. Oxyfluorfen at 35 g ha−1 plus organosilicone surfactant caused 42% onion injury at 12 d after three sequential applications. Onion treated with bromoxynil at 18 g ha−1 plus high surfactant oil concentrate had lower fresh weight (0.7 g) compared to methylated seed oil (MSO) (1.2 g) or petroleum oil concentrate (POC) (1.3 g) at the same bromoxynil rate. The addition of nonionic surfactant to bromoxynil, averaged across bromoxynil rates, provided 17 and 39% control of redroot pigweed and common lambsquarters, respectively. Redroot pigweed control with oxyfluorfen at 35 or 18 g ha−1 plus any tested adjuvant was excellent (≥ 93%). Results suggested the use of POC or MSO with either oxyfluorfen or bromoxynil for subsequent field trials because of similar common lambsquarters and redroot pigweed control and onion safety.

La competencia temprana durante la temporada de crecimiento puede causar pérdidas sustanciales de rendimiento en la cebolla. Oxyfluorfen y bromoxynil son opciones de herbicidas POST para el control de malezas cuando la cebolla ha desarrollado dos hojas, lo cual toma frecuentemente de 4 a 6 semanas. En condiciones de invernadero, se evaluó la seguridad en la producción de cebolla y el control de malezas de aplicaciones múltiples de oxyfluorfen a 35 y 18 g ai ha−1 y de bromoxynil a 35 y 18 g ae ha−1 con adyuvantes. Oxyfluorfen a 35 g ha−1 más surfactante organosilicone causó 42% de daño en la cebolla a 12 días después de tres aplicaciones secuenciales. Cebolla tratada con bromoxynil a 18 g ha−1 más surfactante de aceite de alta concentración tuvo un peso fresco menor (0.7 g) en comparación con el aceite metilado de semilla (MSO) (1.2 g) o el concentrado de aceite de petróleo (POC) (1.3 g) a la misma dosis de bromoxynil. La adición de surfactante no-iónico al bromoxynil, promediando todas las dosis de bromoxynil, brindó 17 a 39% de control de Amaranthus retroflexus y Chenopodium album, respectivamente. El control de A. retroflexus con oxyfluorfen a 35 ó 18 g ha−1 más cualquiera de los adyuvantes evaluados fue excelente (≥93%). Los resultados sugirieron el uso de POC o MSO ya sea con oxyfluorfen o bromoxynil para estudios de campo futuros por el control similar de A. retroflexus y C. album además de su seguridad en la cebolla.


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Early-Season Weed Control Using Herbicides with Adjuvants in Direct-Seeded Onion

  • James R. Loken (a1) and Harlene M. Hatterman-Valenti (a1)


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