Sumatran Fleabane (Conyza sumatrensis) Control in No-Tillage Soybean with Diclosulam Plus Halauxifen-Methyl

• Published in: Weed technology 2017-03, Vol.31 (2), p.184-192
• Main Authors: Braz, Guilherme B. P, Oliveira, Rubem S, Zobiole, Luiz Henrique S, Rubin, Rogério S, Voglewede, Christopher, Constantin, Jamil, Takano, Hudson K
• Format: Article
• Language: English
• Subjects: 2,4-D; Arylpicolinate herbicide; auxin mimic herbicide; burndown; Corn; Crop yield; Crops; Effectiveness; fallow weed management; Glyphosate; Herbicides; Mixtures; Planting; pre-plant application; Seeds; Soybeans; Tillage; WEED MANAGEMENT-MAJOR CROPS; Weeds
• ISSN: 0890-037X; 1550-2740
• DOI: 10.1017/wet.2016.28

Due to the limited availability of selective herbicides to control Sumatran fleabane after soybean emergence, it is essential to develop new options that provide effective control prior to planting. A new herbicide formulation containing diclosulam + halauxifen-methyl was evaluated for effectiveness at two Sumatran fleabane plant heights (5 to 10 cm, and 10 to 50 cm) and for soybean selectivity when applied at 7 or 3 d before planting. Combined results from the two sites showed that diclosulam+ halauxifen, applied either alone or in a tank mixture with glyphosate, and the tank mixture of diclosulam + 2,4-D amine + glyphosate are effective at all rates tested to control Sumatran fleabane in preplant applications. Crop response was observed with applications 7 days before planting at only one of the sites. A rate-dependent crop response was observed for pre-plant applications performed 3 days before soybean planting. However, crop yield was not significantly affected for either timing across all rates. All rates tested of diclosulam + halauxifen in this study were considered safe to soybean. Nomenclature: Diclosulam; glyphosate; halauxifen, 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylic acid; 2,4-D; Sumatran fleabane, Conyza sumatrensis (Retz.) E. Walker; soybean, Glycine max L. Merr.