Assessment of dicamba and 2,4-D residues in Palmer amaranth and soybean

• DOI: 10.1017/wet.2023.60
• Publication Date: 2023-09-04T01:01:58Z
• Authors: Maria Leticia Zac...; Jason K. Norsworthy; Leonard B. Piveta; L. Tom Barber; Andy Mauromoustakos
• Keywords: Dicamba; Residue (chemistry)

Abstract Off-target movement of 2,4-D and dicamba is sometimes to blame as the cause symptoms observed in weeds growing production fields. Pesticide regulatory authorities routinely sample tissues or crops from fields under investigation for potential illegal use auxin herbicides. This research aimed determine if analytical tests herbicide residue on soybean Palmer amaranth vegetation treated with could be used differentiate between rates applied how levels decay over a 1-mo interval. Four each (1X, 0.1X, 0.01X, 0.001X) were applied, 1X rate assumed 560 1,065 g ae ha −1 , respectively. Experiments included dicamba- 2,4-D-resistant (Xtend® Enlist® traits, respectively) categorized by size (8 15 cm, 20 30 35 50 cm height). Analytical results show that residues detected above detection limits 0.04 µg 0.004 2,4-D, respectively, particularly samples 0.1X 2,4-D. Nondetections frequent, even early 2 3 d after treatment (DAT), 0.01X 0.001X dicamba. Residues declined rapidly Xtend® The severity symptomology generally agreed ability detect plant tissue amaranth, whereas soybean, this was not always case. Hence detecting both vegetation, along visible plants during investigations, would indicate an earlier direct application rather than off-target being detection.