Efficacy and Economics of Leafy Spurge (Euphorbia esula) Control in Pasture

Abstract

Herbicide treatments containing the butoxyethanol ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid], the dimethylamine salt of dicamba (3,6-dichloro-o-anisic acid), the potassium salt of picloram (4-amino-3,5,6-trichloropicolinic acid), and the isopropylamine salt of glyphosate [N-(phosphonomethyl)glycine] were applied for 6 yr to a pasture in east-central South Dakota containing leafy spurge (Euphorbia esulaL. ♯ EPHES). Several treatments resulted in leafy spurge control exceeding 90%. Mean herbage dry-weight yield in treated plots was 2340 kg/ha, a 67% increase over untreated plots. Forage yields did not significantly differ among treatments controlling 90% or more leafy spurge. Marginal net return over marginal cost from herbicide treatments ranged from $35 to –$63/ha. Treatments providing satisfactory leafy spurge control with minimum economic risk were annual spring applications of 2,4-D at 1.7 kg ae/ha or dicamba + 2,4-D at 0.6 + 1.1 kg ae/ha and the biannual application of 2,4-D at 0.8 kg ae/ha.