Residual Herbicide Effect on Interseeded Annual Clover in Southern Forage Systems

Abstract

Across the southeastern United States, pyridine carboxylic acid herbicides are widely used for broadleaf weed control in permanent grass pastures. This family of herbicides has proved very successful for controlling most broadleaf weeds commonly present in southeastern pastures and hayfields. In the southern United States, producers have expressed concern when overseeding legume species into warm-season perennial sods following application of commonly used pyridine carboxylic acid herbicides, as legumes are generally highly sensitive to this herbicide family. Field experiments were established to evaluate two herbicide treatment programs (residual vs nonresidual) on crimson clover overseeded into bermudagrass sod. The residual herbicide program included aminopyralid plus 2,4-D (0.09 + 0.7 kg ae ha–1), and the nonresidual program included triclopyr plus fluroxypyr (0.63 + 0.21 kg ae ha–1) plus 2,4-D (1.12 kg ae ha–1). Herbicide programs were applied at two key timings: in spring (May) and early summer (June). Spring applications were also evaluated when used in single vs repeated annual application. Our results did not indicate soil residual herbicide issues for crimson clover planted in the fall following spring or early-summer application of aminopyralid + 2,4-D at either location. Additionally, there were no cumulative negative impacts on crimson clover following 2 yr of spring herbicide application. Crimson clover cover, however, strongly decreased as grass and weed cover increased––an event that may be related to greater interspecific competition at higher levels of grass and weed cover. Soil fertility, weather, and competition from resident annual grasses and weeds strongly influenced productivity, suggesting that changes in pasture dynamics had a greater influence on clover productivity than did herbicide treatment or timing of application.

Impact of soil residual auxin herbicide on seedling emergence and biomass differs between soil types, water pulse event, and seedling species

“…The application of synthetic-auxin herbicides to control woody plant encroachment is a commonly used and effective ecological restoration tool (Hamilton 2004;Tunnell et al 2006;Eddy et al 2020). A range of nontarget impacts on seed emergence and young seedling growth due to soil residual synthetic-auxin herbicide activity has been shown, from negative impacts to no observed impacts (Wagner & Nelson 2014;Douglass et al 2016;Tucker et al 2018). However, abiotic conditions such as soil type or post-herbicide-application water pulses (Hirsch et al 2012) can interact with herbicide application and species to influence these outcomes.…”

4-Hydroxyphenylpyruvate Dioxygenase Inhibitors: From Molecular Design to Synthesis

“…Herbicides containing natural product structures have short half-lives and few halogen substituents. Cinnamic acid is a naturally occurring substance with notable biological activity. , The innovative compounds, derivatives of 3-hydroxy-2-cinnamoyl-2-en-1-one, were discovered through the combination of the triketone skeleton with a cinnamic acid fragment (SI, Scheme S14). Bioactivity assessments revealed that compound S37 showed better At HPPD inhibition, herbicidal effectiveness, and crop selectivity in comparison to mesotrione.…”

Design, Synthesis, Structure–Activity Relationship, Molecular Docking, and Herbicidal Evaluation of 2-Cinnamoyl-3-Hydroxycyclohex-2-en-1-one Derivatives as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors

“…Many new bioactive structures have been generated from natural products, secondary metabolites, or their derivatives in pesticide design . Natural product-based herbicides have short environmental half-lives and fewer halogen substituents . Glufosinate is obtained from the metabolites of Streptomyces in plants, and it has great herbicidal activity that controls most annual perennial monocotyledon and dicotyledon weeds .…”

“…22 Natural product-based herbicides have short environmental half-lives and fewer halogen substituents. 23 Glufosinate is obtained from the metabolites of Streptomyces in plants, and it has great herbicidal activity that controls most annual perennial monocotyledon and dicotyledon weeds. 24 Cinnamic acid, the natural aromatic carboxylic acid, is obtained from cinnamon bark or benzoin, and its derivatives play an important role in bioactivity and drug design.…”