Soybean Development and Yield as Affected by Three Postemergence Herbicides

Abstract

1-methyl-2-oxyethyl 5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzoate] typically cause necrosis of Field experiments were conducted during 3 yr at four locations in soybean leaf tissue present at the time of application Illinois and three locations in Iowa to evaluate the influence of soybean [Glycine max (L.) Merr.] planting date and postemergence herbicide and crinkling and necrosis of leaves that emerge shortly application timing on soybean injury and grain yield. Glyphosate after application (Kapusta et al., 1986; Wichert and [N-(phosphonomethyl)glycine] at 1120 g a.e. ha Ϫ1 did not cause visual Talbert, 1993). Soybean stunting and chlorosis was obsoybean injury or reduce yield. Acifluorfen [5-[2-chloro-4-(trifluoroserved from herbicides that inhibit the ALS enzyme methyl)phenoxy]-2-nitrobenzoic acid] at 420 g a.i. ha Ϫ1 , and imazesuch as imazethapyr (Hart and Roskamp, 1998; Hart et thapyr [2-[4,5-hydro-methyl-4-(1-methylethyl)-5-oxo-1H-imidazolal., 1997). Recent studies have also reported injury to 2-yl]-5-ethyl-3-pyridinecarboxylic acid] at 70 g a.i. ha Ϫ1 caused visual glyphosate-resistant soybean treated with glyphosate soybean injury at 5 to 7 and 21 to 24 d after herbicide application (Weber and Kapusta, 1998; Young and Young, 2000). (DAA). Overall soybean injury was greater with the late plantingAlthough soybean plants usually recover from herbicide date compared with the early planting date. Chlorosis and stunting injury as the season progresses, producers question if at 5 to 7 DAA was greater from acifluorfen and imazethapyr at the early (V2-V3 soybean stage) compared with the late (V5-V6 soybean

Tolerance of Maize (<i>Zea mays</i> L.) and Soybean [<i>Glycine max</i> (L.) Merr.] to Late Applications of Postemergence Herbicides

“…The exception to this is maize, which can tolerate over two-fold of the maximum labeled dose of glyphosate applied at the 10-leaf stage with minimal injury and little to no yield loss [9]. Furthermore, to the best of our knowledge, few studies have been conducted in the absence of confounding weed competition effects that examine both a range of herbicides comparing relative crop tolerance [10] and the tolerance of crops to a late POST herbicide application [11]. Therefore, the objective of this research was to determine the tolerance of maize and soybean to a late application of select POST herbicides in the absence of weed interference.…”

Effect of five postemergence herbicides on red clover shoot and root growth in greenhouse studies

“…Several studies have shown that some herbicides can have initial phytotoxic effects, although seedlings usually recover without severe damage, and yield loss are not observed (Díaz et al 1992;Ivany et al 2002;Thomas et al 1994;Tonks et al 1991;Volenberg et al 2002;Young et al 2003). In other studies, however, various clover species were exposed and evaluated for tolerance to different herbicides including pendimethalin and metolachlor (Tharp and Kells 2000), bentazon and 2,4-D (Evers et al 1993), 2,4-D and dicamba (Griffin et al 1984), and MCPA and 2,4-DB (Conrad and Stritzke 1980); in all cases, yield and persistence of the legume were markedly reduced.…”

Simulated mesotrione drift followed by glyphosate, imazethapyr, bentazon or glyphosate plus chlorimuron in soybean

“…In susceptible species, it causes bleaching followed by growth cessation and necrosis (Pallett et al 1998). Young et al (2003a) reported that mesotrione applied POST to soybean at 1.1, 3.2, and 11 g a.i. ha…”

“…Imazethapyr and chlorimuron are acetolactate synthase (ALS) inhibitors that block branched-chain amino acid (valine, leucine, isoleucine) biosynthesis (Vencill 2002). Imazethapyr can cause some initial injury to soybean Young et al 2003b). Soybean has also shown some injury shortly after application of chlorimuron (Culpepper et al 2000).…”