Field experiments were conducted in 2011 and 2012 in Belle Glade, FL to evaluate the response of sweet corn and weed control to pyroxasulfone on high-organic-matter soils in the Everglades Agricultural Area (EAA) of southern Florida with the use of dose-response curves. Pyroxasulfone was applied PRE at 31.25, 62.5, 125, 250, 500, and 1,000 g ai ha⁻¹ on soil with 80% organic matter. Dose-response curves based on a three-parameter log-logistic model were used to determine pyroxasulfone rate required to provide 90% control (ED₉₀) of spiny amaranth, common lambsquarters, and common purslane in sweet corn. The ED₉₀ values for spiny amaranth, common lambsquarters, and common purslane control were 209, 215, and 194 g ha⁻¹ of pyroxasulfone, respectively, at 21 d after treatment (DAT). At 42 DAT, the ED₉₀ values for spiny amaranth, common lambsquarters, and common purslane control were 217, 271, and 234 g ha⁻¹ of pyroxasulfone, respectively. Sweet corn yield increased with increasing rates of pyroxasulfone. An estimated 214 g ha⁻¹ of pyroxasulfone was required to maintain sweet corn yield at 90% level of the weed-free yield. In addition, pyroxasulfone did not result in sweet corn injury. These results indicate that pyroxasulfone can provide effective weed control in sweet corn on high-organic-matter soils of the EAA.

Nomenclature: Pyroxasulfone; common lambsquarters, Chenopodium album L. CHEAL; common purslane, Portulaca oleracea L. POROL; spiny amaranth, Amaranthus spinosus L. AMASP; sweet corn, Zea mays L.

Se realizaron experimentos de campo en 2011 y 2012 en Belle Glade, FL para evaluar la respuesta del maíz dulce y el control de malezas a pyroxasulfone en suelos con alta contenido de materia orgánica en el Área Agrícola de Everglades (EAA) en el sur de Florida, usando curvas de respuesta a dosis. Se aplicó pyroxasulfone PRE a 31.25, 62.5, 125, 250, 500 y 1,000 g ai ha⁻¹ en suelo con 80% materia orgánica. Se usaron curvas de respuesta a dosis basadas en un modelo log-logístico de tres parámetros para determinar la dosis requerida de pyroxasulfone para obtener 90% de control (ED₉₀) de Amaranthus spinosus, Chenopodium album, y Portulaca oleracea en maíz dulce. Los valores de ED₉₀ para el control de A. spinosus, C. album, y P. oleracea fueron 209, 215 y 194 g ha⁻¹ de pyroxasulfone, respectivamente. El rendimiento del maíz dulce incrementó con dosis crecientes de pyroxasulfone. Se requirió un estimado de 214 g ha⁻¹ de pyroxasulfone para mantener el rendimiento del maíz dulce a un nivel de 90% del rendimiento con cero malezas. Adicionalmente, pyroxasulfone no causó daño al maíz dulce. Estos resultados indican que pyroxasulfone puede brindar control efectivo de malezas en maíz dulce en suelos con alto contenido de materia orgánica en el EAA.