How to translate text using browser tools
21 August 2019 Effect of soybean growth stage on sensitivity to sublethal rates of dicamba and 2,4-D
Alanna B. Scholtes, Benjamin P. Sperry, Daniel B. Reynolds, J. Trenton Irby, Thomas W. Eubank, L. Thomas Barber, Darrin M. Dodds
Author Affiliations +
Abstract

Field experiments were conducted in 2012 and 2013 across four locations for a total of 6 site-years in the midsouthern United States to determine the effect of growth stage at exposure on soybean sensitivity to sublethal rates of dicamba (8.8 g ae ha-1) and 2,4-D (140 g ae ha-1). Regression analysis revealed that soybean was most susceptible to injury from 2,4-D when exposed between 413 and 1,391 accumulated growing degree days (GDD) from planting, approximately between V1 and R2 growth stages. In terms of terminal plant height, soybean was most susceptible to 2,4-D between 448 and 1,719 GDD, or from V1 to R4. However, maximum susceptibility to 2,4-D was only between 624 and 1,001 GDD or from V3 to V5 for yield loss. As expected, soybean was sensitive to dicamba for longer spans of time, ranging from 0 to 1,162 GDD for visible injury or from emergence to R2. Likewise, soybean height was most affected when dicamba exposure occurred between 847 and 1,276 GDD or from V4 to R2. Regarding grain yield, soybean was most susceptible to dicamba between 820 and 1,339 GDD or from V4 to R2. Consequently, these data indicate that soybean response to 2,4-D and dicamba can be variable within vegetative or reproductive growth stages; therefore, specific growth stage at the time of exposure should be considered when evaluating injury from off-target movement. In addition, application of dicamba near susceptible soybean within the V4 to R2 growth stages should be avoided because this is the time of maximum susceptibility. Research regarding soybean sensitivity to 2,4-D and dicamba should focus on multiple exposure times and also avoid generalizing growth stages to vegetative or reproductive.

Nomenclature: Dicamba; 2,4-D; soybean; Glycine max L. Merr

© Weed Science Society of America, 2019. This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use or in order to create a derivative work.
Alanna B. Scholtes, Benjamin P. Sperry, Daniel B. Reynolds, J. Trenton Irby, Thomas W. Eubank, L. Thomas Barber, and Darrin M. Dodds "Effect of soybean growth stage on sensitivity to sublethal rates of dicamba and 2,4-D," Weed Technology 33(4), 555-561, (21 August 2019). https://doi.org/10.1017/wet.2019.39
Received: 10 September 2018; Accepted: 22 April 2019; Published: 21 August 2019
KEYWORDS
Auxin herbicide
maximum susceptibility
soybean injury
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top