Evaluation of Very-Long-Chain Fatty Acid-Inhibiting Herbicides in Arkansas Rice Production

<p>Because of the evolution of herbicide-resistant weeds, such as barnyardgrass and red rice in rice, there is a need for alternative herbicide sites of action. Very-long-chain fatty acid (VLCFA)-inhibiting herbicides are not labeled for use in U.S. rice production; however, this site of action (SOA) has been used with success in Asian rice. The VLCFA-inhibiting herbicides pethoxamid, pyroxasulfone, acetochlor, and S-metolachlor were evaluated for rice tolerance and control of commonly problematic weeds in Arkansas rice at various rates and application timings. Pyroxasulfone and S-metolachlor were deemed unfit for use in rice production because of negative effects on rice visual injury, rough rice yield, height, shoot density, and heading. Pethoxamid and acetochlor were used with little detriment to the rice crop when applied no earlier than the 1-lf growth stage. Along with minimal rice injury, pethoxamid controlled barnyardgrass all season when used in a program with other common rice herbicides such as clomazone, imazethapyr, or quinclorac. Considering the minimal injury observed, pethoxamid and acetochlor should be considered for integration into U.S. rice production to represent a unique herbicide SOA to use in rotation, sequential application, or tank mixtures with other rice herbicides. </p> <p>Nomenclature: Acetochlor; pethoxamid; pyroxasulfone; S-metolachlor; barnyardgrass, Echinochloa crus-galli (L.) Beauv.; red rice, Oryza sativa var. sylvatica L.; rice, Oryza sativa L. </p> <p>Key words: weed control, herbicide-resistant weeds, herbicide sites of action </p>

Name thesis:degree_name

Master of Science in Crop, Soil & Environmental Sciences (MS)

Level thesis:degree_level

Thesis

Year dc:date.available

2017

Author dc:creator

• Godwin, John Ansley

Advisor dc:contributor.advisor

• Norsworthy, Jason K.

Contributors dc:contributor

• Scott, Robert C.
• Roberts, Trenton L.

• Herbicide-resistant Weeds
• Herbicide Sites Of Action
• Weed Control
• Agronomy and Crop Sciences
• Weed Science

Repository record dc:identifier

https://scholarworks.uark.edu/etd/2609

OAI identifier oai:identifier

oai:scholarworks.uark.edu:etd-4158