Acetic acid for weed control in potato (Solanum tuberosum L.)

Abstract

Potatoes (Solanum tuberosum L.) are produced in all Canadian provinces, and interest has increased in the use of non-synthetic chemicals and organic techniques to provide weed control. Acetic acid has been suggested as a chemical that could potentially provide weed control in potato production. We examined glacial acetic acid and Ecoclear (30% acetic acid, 1.0% naptha solvent and 1.0% trimethyl benzene) for effectiveness in controlling weeds in potatoes when applied in a 30-cm-wide band over the potato row as well as their effect on potato yield components in three experiments repeated over 2 yr. The effects of time of application and volume of application were also examined. Glacial acetic acid at 10% concentration did not injure potato foliage, but at 20 and 30% concentration it injured emerged potato foliage. A concentration of 20% acetic acid was needed to provide acceptable weed control levels of lambs-quarters, corn spurry and wild buckwheat. Marketable yield was reduced by 20 and 30% acetic acid to below the standard herbicide treatment. Sequential applications of acetic acid at concentrations of 10, 20 or 30%, applied 7-10 d apart, caused slightly greater injury and yield was 10 to 15% less than in the single application. Ecoclear applied to emerged weeds and before potato emergence did not injure potato foliage, but when applied post-emergence it caused severe, but short lived, potato injury. Ecoclear gave greater than 80% control of lambs-quarters, corn spurry and wild radish. Potato marketable yield was comparable with that achieved with a herbicide and was reduced only in one year by Ecoclear applied post-emergence. Weed control was 18% or less when Ecoclear was applied at 200 L ha-1, 54 to 74% when applied at 400 L ha -1 and 91 to 95% when applied at 800 L ha-1 volume of application.