1 April 2006 Efficacy and Tolerance of Flumioxazin on Sweetpotato (Ipomoea batatas)
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Experiments were conducted at three locations in Louisiana in 2002 and 2003 to evaluate flumioxazin (36, 72, or 109 g ai/ha) applied pretransplant (PRE) or post-transplant (POST) to sweetpotato. All treatments were applied immediately before or after sweetpotato transplanting to weed-free beds. PRE applications caused 4% or less injury with any rate of flumioxazin at 9 or 18 d after transplanting (DATr) compared with 18 to 20% injury at 9 DATr and 6 to 14% at 18 DATr with 72 or 109 g/ha POST, respectively. Injury from PRE applications of flumioxazin were not different from injury with clomazone (840 g ai/ha) applied POST. Injury at Chase, LA, in 2002 was 8% and less with flumioxazin PRE, but 35 to 83% with flumioxazin POST and appeared to be due to the use of greenhouse-grown cuttings instead of field-grown cuttings, which were used in the other two experiments. There was no interaction between experiments for sweetpotato yield. Plots treated with flumioxazin PRE or 36 g/ha POST yielded greater than sweetpotato treated with clomazone for U.S. No. 1 and 2 grade yield as well as total marketable yield. No differences were observed in yellow nutsedge control with any rate of flumioxazin. At 34 or 50 DATr, flumioxazin controlled yellow nutsedge 73 to 85% with 72 or 109 g/ha applied PRE or POST. Flumioxazin, regardless of application timing or rate, controlled carpetweed and spiny amaranth at least 86%. A similar experiment in Mississippi evaluated tank-mixes of flumioxazin (36, 72, or 109 g/ha) and clomazone (840 g/ha) applied PRE or POST. No sweetpotato injury was observed with flumioxazin PRE. However, injury from flumioxazin POST increased with increased rates (18 to 50% at 18 DATr and 16 to 93% at 25 DATr). Weed control was greater than 80% with all treatments.

Nomenclature: Clomazone; flumioxazin; broadleaf signalgrass, Brachiaria platyphylla (Griseb.) Nash #3 BRAPP; carpetweed, Mollugo verticillata L. # MOLVE; entireleaf morningglory, Ipomoea hederacea var. integriuscula Gray # IPOHE; pitted morningglory, Ipomoea lacunosa L. # IPOLA; redroot pigweed Amaranthus retroflexus L. # AMARE; spiny amaranth, Amaranthus spinosus # AMASP; yellow nutsedge, Cyperus rotundus L. # CYPES; sweetpotato, Ipomoea batatas (L.) Lam. ‘Beauregard’.

Additional index words: Clomazone, Amaranthus retroflexus, Amaranthus spinosus, Brachiaria platyphylla, Cyperus rotundus, Ipomoea hederacea var. integriuscula, Ipomoea lacunosa, Mollugo verticillata, AMARE, AMASP BRAPP, CYPES, IPOHE, IPOLA, MOLVE.

Abbreviations: DATr, days after transplanting; PRE, pretransplant; POST, post-transplant.

STEVEN T. KELLY, MARK W. SHANKLE, and DONNIE K. MILLER "Efficacy and Tolerance of Flumioxazin on Sweetpotato (Ipomoea batatas)," Weed Technology 20(2), 334-339, (1 April 2006). https://doi.org/10.1614/WT-04-330R1.1
Published: 1 April 2006
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