The Influence of 2,4-D Formulation on Hard Water Antagonism.

The Influence of 2,4-D Formulation on Hard Water Antagonism

Herbicides are formulated to improve handling and to increase the efficacy of the product. The herbicide 2,4-D comes in many formulations that are used to control broadleaf weeds. The goal of this experiment was to determine if different 2,4-D formulations are similarly antagonized by hard water. Formulation combinations of 2,4-D included various amine salts and esters, which were all applied at the same acid equivalent rate (1.6 kg ae ha^-1). Formulas tested included 2,4-D dimethylamine, 2,4-D (mono)methylamine, 2,4-D isopropylamine, 2,4-D diethanolamine, 2,4-D isooctyl ester, and 2,4-D butoxyethyl ester. A nontreated check was included for comparison. Dandelions (Taraxacum officinale) were grown in a greenhouse and treated with 2,4-D formulations tank mixed with either soft water (0 ppm CaCO₃) or hard water (600 ppm CaCO₃). Plants were rated for epinasty and control and were destructively harvested 4 weeks after application. Amine formulations were antagonized by hard water, which is similar to previous research on 2,4-D dimethylamine. Two ester formulations were not antagonized by hard water. Results are consistent with the fact that water soluble 2,4-D amine formulations are subject to hard water antagonism, but not the insoluble 2,4-D esters formulated as emulsifiable concentrates.   

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