Annette Chandler

Impact of Application Rate, Timing, and Indaziflam Formulation on Early Postemergence Control of Oxalis stricta

Although primarily used as an effective PRE herbicide, indaziflam has been shown to provide early POST control of some weeds commonly found in nursery production. Previous investigation on the early POST efficacy of indaziflam focused on the liquid formulation, and the ability of the granular formulation to provide early POST weed control is unknown. Nursery trials were conducted to evaluate early POST control of oxalis using two formulations of indaziflam. Oxalis seeds were surface sown to nursery containers at two separate dates and grown until they reached the two- to four-leaf stage (2-4L) and six- to eight-leaf stage. Both growth stages were treated with indaziflam at 12.6, 25.1, 50.2, and 100.4 g ai ha−1 using either a granular (G) or liquid (SC) formulation. A chemical control treatment (glyphosate) and a nontreated control were also included for comparison. The SC formulation provided > 90% control of both oxalis growth stages at all four rates and was similar to glyphosate. The G formulation at 12.6 and 25.1 g ha−1 only provided marginal control, but overall performed similarly to the SC formulation at the 50.2 and 100.4 g ha−1 rate in most experiments. In contrast to the SC formulation, the G formulation is labeled for use over the top of container-grown nursery crops. Results of this research indicate that in areas where oxalis is the primary weed of concern, the G formulation of indaziflam could be applied to control small oxalis up to the 2-4L stage at the currently labeled rate (50.2 g ha−1). Nomenclature: Indaziflam; glyphosate; Oxalis stricta L. Aunque se usa principalmente como un herbicida PRE efectivo, indaziflam ha mostrado poder brindar control POST temprano de varias especies de malezas comúnmente encontradas en la producción de almácigas en viveros. Investigación previa sobre la eficacia de indaziflam en POST temprano se enfocó en la formulación líquida, pero se desconoce la habilidad de la formulación granular de brindar control POST temprano de malezas. Se realizaron experimentos en vivero para evaluar el control POST temprano de Oxalis usando dos formulaciones de indaziflam. Semillas de Oxalis fueron sembradas en la superficie de contenedores en dos fechas separadas y las plantas fueron crecidas hasta alcanzar los estadios de dos a cuatro hojas (2-4L) y seis a ocho hojas. Ambos estadios de crecimiento fueron tratados con indaziflam a 12.6, 25.1, 50.2, y 100.4 g ai ha−1 usando, ya fuese la formulación granular (G) o líquida (SC). También se incluyó un tratamiento testigo químico (glyphosate) y un testigo sin tratamiento para fines de comparación. La formulación SC brindó >90% de control de Oxalis en ambos estadios de crecimiento con las cuatro dosis y este control fue similar al de glyphosate. La formulación G a 12.6 y 25.1 g ha−1 solamente brindó un control marginal, pero su desempeño general fue similar a la formulación SC a dosis de 50.2 y 100.4 g ha−1 en la mayoría de los experimentos. En contraste con la formulación SC, la formulación G está registrada para uso en cultivos de vivero aplicada sobre plantas crecidas en contenedores. Los resultados de esta investigación indican que en áreas donde Oxalis es la principal maleza, la formulación G de indaziflam podría ser aplicada para el control de plantas de Oxalis pequeñas hasta el estadio de 2-4 L a la dosis de etiqueta actual (50.2 g ha−1).

Preemergence and Postemergence Control of Artilleryweed (Pilea microphylla) in Container Nurseries and Landscapes

Artilleryweed is an annual or short-lived perennial weed that is becoming increasingly problematic in nurseries and landscapes in tropical and subtropical environments. Currently, no herbicide recommendations exist for management of artilleryweed. Objectives of this trial were to evaluate PRE and POST herbicides for efficacy on artilleryweed. All studies were conducted in Apopka, FL in a shaded greenhouse. Herbicides evaluated for POST control included diquat, dimethenamid-P, flumioxazin, glufosinate, glyphosate, indaziflam, oxadiazon, pelargonic acid, sulfentrazone and sulfosulfuron applied at their highest labelled rates to mature (10 to 12 cm height) artilleryweed. For PRE experiments, pots were overseeded with artilleryweed seed and treated with dimethenamid-P, indaziflam, isoxaben, oxadiazon, oxyfluorfen + prodiamine, oxyfluorfen + pendimethalin, pendimethalin, pendimethalin + dimethenamid-P, prodiamine, prodiamine + isoxaben, S-metolachlor, or trifluralin + isoxaben. When assessing both initial fresh weight and regrowth, flumioxazin and glufosinate provided the most consistent POST control when applied at the highest labelled rate, although regrowth did occur following application with glufosinate. All PRE herbicides evaluated provided over 90% control of artilleryweed with the exception of isoxaben and trifluralin + isoxaben. Results indicate that several effective options exist for artilleryweed management, but more effective control will likely be achieved when herbicides are applied PRE. Nomenclature: Dimethenamid-P; diquat; flumioxazin; glufosinate; glyphosate; indaziflam; isoxaben; oxadiazon; oxyfluorfen; pelargonic acid; pendimethalin; prodiamine; S-metolachlor; sulfentrazone; sulfosulfuron; trifluralin; artilleryweed, Pilea microphylla (L.) Liebm.