Performance consistency of reduced atrazine use in sweet corn

• Published in: Field crops research Vol. 121; no. 1; pp. 96 - 104
• Main Authors: Williams, Martin M., Boydston, Rick A., Peachey, R. Ed, Robinson, Darren
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 28.02.2011; [Amsterdam]: Elsevier
• Subjects: application rate; Atrazine; Atrazine, Path analysis, Regional scale, Risk, Weed management; broadleaf weeds; canopy; crop yield; crop-weed competition; field experimentation; grass weeds; integrated weed management; light; light interception; pesticide use reduction; plant density; postemergent weed control; risk reduction; sweetcorn; tembotrione; weed control; Zea mays; Oregon; Ontario; Illinois; Washington; North America; Atrazine, Path analysis, Regional scale, Risk, Weed management
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2010.11.020

▶ Postemergence atrazine reduced occurrence of weed control failure and crop losses. ▶ Greater crop competitiveness decreased risk associated with using less atrazine. ▶ Reduction in atrazine would necessitate improvement in other aspects of weed control. Atrazine is the most widely used herbicide in North American corn production; however, additional restrictions on its use in the near future are conceivable. Currently, a majority of commercial sweet corn fields suffer losses due to weeds, despite widespread use of atrazine. Field experiments were conducted in the primary North American production areas of sweet corn grown for processing to determine the implications of further reductions in atrazine use on weed control and crop yield. A range of atrazine doses (0–1120 g ha −1) applied postemergence with tembotrione (31 g ha −1) were tested in two hybrids differing in canopy architecture and competitive ability with weeds. Atrazine applied postemergence reduced risk (i.e. more variable outcomes) of poor herbicide performance. Atrazine doses up to 1120 g ha −1 with tembotrione improved grass control and broadleaf weed control in five of eight and seven of eight environments, respectively. Of the three environments which had particularly low broadleaf weed control (<50%) with tembotrione alone, sweet corn yield was improved with atrazine. Hybrid ‘Code128’ produced a taller, denser canopy which was more efficient at capturing light and competing with weeds than ‘Quickie’. As a result, greater crop competitiveness decreased risk of incomplete weed control as atrazine dose was reduced. Atrazine's contribution to weed control and yield protection was greatest when other aspects of weed management resulted in poor weed control. Should atrazine use be further restricted or banned altogether, this research demonstrates the importance of improving other aspects of weed management systems such as herbicidal and non-chemical tactics.