Soybean [Glycine max(L.)] Response to Lactofen

Abstract

Field studies were conducted in 1987 and 1988 to evaluate the vegetative response of soybeans to early postemergence applications of lactofen and to measure crop recovery. Soybean injury 4 d after treatment (DAT) averaged 29 and 34% with 0.22 and 0.44 kg ai ha−1of lactofen, respectively. Severity of leaf injury depended on leaf size at the time of lactofen application. Leaf area of soybean trifoliates one through three were reduced 30 to 45% at 12 DAT but recovered by 26 DAT. Later emerging trifoliates were not affected. Fresh weights of lactofen-treated soybeans were less than those of untreated plants 4, 8, and 16 DAT, and dry weights were less at 16 and 26 DAT. Lactofen reduced stomatal conductance of expanded leaves but had no effect on unexpanded leaves. Soybean yields did not differ with lactofen treatment.

Input‐based Stress Management Fails to Increase Soybean Yield in Kentucky

“…Lee et al (2008) showed that if canopy light interception approached 90% at R1 and reached 95% by R5, maximum yield would result, likely explaining the similarity in yields. These results for lactofen application during early vegetative growth are similar to previous research showing no yield differences (Harris et al, 1991; Wichert and Talbert, 1993; Nelson et al, 2002; Edwards and Purcell, 2005). Additionally, lactofen‐treated plants were visually similar to untreated plants and application of lactofen did not affect branch nodes, branch pods, or branch seeds, indicating that the lactofen did not damage the apical meristem or affect soybean branching.…”

“…While numerous studies have shown the importance of branching in soybean yield determination (Herbert and Litchfield, 1982;Board et al, 1990;Carpenter and Board, 1997;Frederick et al, 2001); to our knowledge, no peer-reviewed studies have shown that lactofen application destroys the apical meristem and increases branching. Previous studies have failed to show a yield increase for soybean treated with lactofen in the absence of yield-limiting weed densities (Harris et al, 1991;Wichert and Talbert, 1993;Dann et al, 1999;Nelson et al, 2002;Edwards and Purcell, 2005).…”

“…One herbicide that is used to stress early-vegetative soybeans is lactofen [[2-ethoxy-1-methyl-2-oxoethyl-5-[2-chloro-4-(trifluoromethyl)-phenoxy]-2-nitrobenzoate], a protoporphyringoen oxidase herbicide registered for broadleaf weed control in soybean. Lactofen causes burning and bronzing of the leaf tissue, leaf necrosis, and possible leaf death (Wichert and Talbert, 1993).…”

Soybean Development and Yield as Affected by Three Postemergence Herbicides

“…The majority of the postemergence herbicides used in soybean are diphenylethers, acetolactate synthase (ALS) inhibitors or glyphosate. Diphenylether herbicides such as acifluorfen and lactofen [( ± )‐2‐ethoxy‐1‐methyl‐2‐oxyethyl 5‐[2‐chloro‐4‐(trifluoromethyl)phenoxy]‐2‐nitrobenzoate] typically cause necrosis of soybean leaf tissue present at the time of application and crinkling and necrosis of leaves that emerge shortly after application (Kapusta et al, 1986; Wichert and Talbert, 1993). Soybean stunting and chlorosis was observed from herbicides that inhibit the ALS enzyme such as imazethapyr (Hart and Roskamp, 1998; Hart et al, 1997).…”

Soybean Growth and Development as Affected by Glyphosate and Postemergence Herbicide Tank Mixtures

“…Research suggests that glyphosate applied to glyphosate‐resistant soybean did not result in significant visual injury (Lich et al, 1997) and allowed rapid canopy closure (Nelson and Renner, 1999). In contrast, postemergence applications of thifensulfuron {3‐[[[[(4‐methoxy‐6‐methyl‐1,3,4‐triazin‐2‐yl)amino]carbonyl]amino]sulfonyl]‐2‐thiophenecarboxylic acid}, lactofen {(±)‐2‐ethoxy‐1‐methyl‐2‐oxoethyl 5‐[2‐chloro‐4‐(trifluoromethyl)phenoxy]‐2‐nitrobenzoate}, and acifluorfen {5‐[2‐chloro‐4‐(trifluoromethyl)phenoxy]‐2‐nitrobenzoic acid} often cause chlorosis, necrosis, or stunting of soybean (Hart and Roskamp, 1998; Kapusta et al, 1986; Wichert and Talbert, 1993). Injury from these herbicides may persist up to 21 DAT although yield loss generally does not occur (Kapusta et al, 1986).…”