With the loss of methyl bromide (MeBr) and high prices of alternatives, tomato growers are applying lower fumigant rates or adopting a reduced system. Without the broad-spectrum control provided by the complete fumigant system, a fallow weed program might be needed to avoid an increase in pest pressure with consecutive years of application of the reduced-fumigant system. Nutsedges are among the pests of interest due to their fast reproduction by underground structures and ability to spread and quickly infest a field. Field trials were conducted between February and December of 2011 in Balm, FL, to evaluate the impacts of fallow treatments, fumigants, and halosulfuron on nutsedge control. The trial design was a split–split plot with main, sub-, and subsubplots being fallow, fumigant, and herbicide treatment, respectively. Fallow treatments were spaced evenly throughout the fallow season and consisted of sequential combinations of cultivation (C) and/or glyphosate (G) applied at 2.24 kg ae ha⁻¹; including: C, CC, G, GG, CG, GC, GCG, and NO (nontreated control). Fumigant treatments included a reduced-fumigant system of 1,3-dichloropropene plus chloropicrin 40:60 (1,3-D pic) at 281 kg ha⁻¹, a complete fumigant system of dimethyl disulfide plus chloropicrin 79:21 (DMDS pic) at 545 kg ha⁻¹, and no fumigant (NoFum). Herbicide treatments were either two POST applications of halosulfuron at 39 g ai ha⁻¹ (Hal) or no halosulfuron (NoHal). In general, the fallow weed treatment GCG was the most effective in reducing nutsedge shoot emergence through the plastic mulch. When the reduced-fumigant system 1,3-D pic was combined with GCG fallow treatment and halosulfuron (GCG:1,3-D pic:Hal), no differences were found between this combination and the complete fumigant system DMDS pic with halosulfuron and combined with CC, G, GG, CG, GC or GCG. This study shows the importance of adding a fallow weed program and halosulfuron to either a reduced or complete fumigation system to minimize the reproduction and growth of nutsedges.

Nomenclature: Chloropicrin (pic); dimethyl disulfide (DMDS); glyphosate; halosulfuron; 1,3-dichloropropene (1,3-D); nutsedge, Cyperus spp.; tomato, Lycopersicon esculentum Mill.

Con la pérdida de methyl bromide (MeBr) y los altos precios de las alternativas, los productores de tomate están aplicando dosis más bajas de fumigante o adoptando un sistema reducido. Sin el control de amplio espectro que se obtiene con un sistema de fumigación completo, un programa de manejo de malezas con barbecho limpio podría ser requerido para evitar el incremento en la presión de esta plaga en los años consecutivos a la aplicación del sistema de fumigación reducida. Cyperus spp. está entre las plagas de interés debido a su rápida reproducción por medio de estructuras subterráneas y su habilidad de dispersarse y rápidamente infestar un campo. Se realizaron experimentos de campo entre Febrero y Diciembre de 2011 en Balm, FL, para evaluar los impactos de tratamientos de barbecho, fumigantes, y halosulfuron sobre el control de Cyperus spp. El diseño del experimento fue parcelas divididas en dos niveles siendo el barbecho, el fumigante y el tratamiento del herbicida la parcela principal, la subparcela y la sub-subparcela, respectivamente. Los tratamientos de barbecho fueron distribuidos en forma uniforme a lo largo de la temporada de barbecho y consistieron en combinaciones secuenciales de cultivo con rastra de discos (C) y/o glyphosate (G) aplicado a 2.24 kg ae ha⁻¹; incluyendo: C, CC, G, GG, CG, GC, GCG, y NO (testigo no tratado). Los tratamientos de fumigantes incluyeron un sistema de fumigación reducida de 1,3-dichloropropene más chloropicrin 40:60 (1,3-D pic) a 281 kg ha^−1<