TITLE:
Control of Glyphosate-Resistant Giant Ragweed (Ambrosia trifida L.) with 2,4-D Followed by Pre-Emergence or Post-Emergence Herbicides in Glyphosate-Resistant Soybean (Glycine max L.)
AUTHORS:
Amit J. Jhala, Lowell D. Sandell, Greg R. Kruger
KEYWORDS:
Corn, Burndown, Giant Ragweed Biomass, Post-Emergence, Pre-Emergence, Resistance Management
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.15,
July
9,
2014
ABSTRACT: Control of glyphosate-resistant giant ragweed is a challenge,
particularly for soybean growers, because of limited effective post-emergence
(POST) herbicide options. Many soybean growers in no-till production systems
use 2,4-D in burndown application for control of broadleaf weeds, including
giant ragweed. Field experiments were conducted at David City, NE, in 2012 and
2013 to evaluate 2,4-D followed by PRE or POST herbicide programs for control
of glyphosate-resistant giant ragweed in glyphosate-resistant soybean. Results
suggested that burndown application of 2,4-D or saflufenacil plus imazethapyr
resulted in 89 to 99% control of giant ragweed at 21 days after treatment.
Burndown-only treatments of S-metolachlor plus metribuzin or sulfentrazone plus
cloransulam resulted in poor control (≤65%) of giant ragweed and reduced
soybean yield (≤ 577 kg·ha-1). Burndown application of 2,4-D
followed by saflufenacil plus imazethapyr, S-metolachlor plus metribuzin, or
sulfentrazone plus cloransulam applied pre-emergence (PRE) or cloransulam,
chlorimuron, fomesafen, imazethapyr, or lactofen in tank-mixtures with
acetochlor applied POST resulted in 87% to 99% giant ragweed control, reduced
density to ≤7 plants m-2, and resulted in soybean yield from 2519 to
3823 kg·ha-1. There was no difference among and between 2,4-D
followed by PRE or POST herbicides for giant ragweed control, density, or
soybean yield, indicating all the two pass herbicide programs were effective.
It is concluded that glyphosate-resistant giant ragweed can be effectively
controlled in soybean by including 2,4-D in burndown program followed by PRE or
POST herbicides tested in this study.