Evaluation of Wick-Applied Glyphosate for Palmer Amaranth (Amaranthus palmeri) Control in Sweetpotato. (September 2016)

• Record Type: Journal Article
• Authors: Meyers, Stephen L.; Jennings, Katherine M.; Schultheis, Jonathan R.; Monks, David W.
• Is Part Of: Weed technology. Volume 30:Number 3(2016)
• Page Start: 765
• Page End: 772
• Publication Date: 2016-09
• Subjects: Glyphosate, -- Palmer amaranth, Amaranthus palmeri S. Wats, -- sweetpotato, Ipomoea batatas L. Lam. 'Beauregard', 'Covington'; Root cracking, -- wick applicator; Weeds -- Periodicals; Weeds -- Control -- Periodicals; 632.5
• DOI: 10.1614/WT-D-16-00024.1
• Languages: English
• ISSNs: 0890-037X

Abstract

Abstract : Studies were conducted in 2007 and 2008 at Clinton, NC to determine the effect of glyphosate applied POST via a Dixie wick applicator on Palmer amaranth control and sweetpotato yield and quality. In 2007, treatments consisted of glyphosate wicked sequentially 6 and 8 wk after transplanting (WAP) and glyphosate wicked sequentially 6 and 8 WAP followed by (fb) rotary mowing 9 WAP. In 2008, treatments consisted of glyphosate wicked once 4 or 7 WAP, wicked sequentially 4 and 7 WAP, mowed once 4 WAP, and mowed 4 WAP fb wicking 7 WAP. In 2008, Palmer amaranth control 6 WAP varied by location and averaged 10 and 58% for plots wicked 4 WAP. Palmer amaranth contacted by the wicking apparatus were controlled, but weeds shorter than the wicking height escaped treatment. Palmer amaranth control 9 WAP was greater than 90% for all treatments wicked 7 WAP. Competition prior to and between glyphosate treatments contributed to large sweetpotato yield losses. Treatments consisting of glyphosate 7 or 8 WAP (in 2007 and 2008, respectively) frequently had greater no. 1 and marketable yields compared to the weedy control. However, jumbo, no. 1, and marketable yields for all glyphosate and mowing treatments were generally less than half the hand-weeded check. Cracked sweetpotato roots were observed in glyphosate treatments and percent cracking (by weight) in those plots ranged from 1 to 12% for no. 1 roots, and 1 to 6% for marketable roots. Findings from this research suggest wicking might be useful in a salvage scenario, but only after currently registered preemergence herbicides and between-row cultivation have failed to control Palmer amaranth and other weed species below the sweetpotato canopy.