ARS | Publication request: AXXE® (pelargonic acid) and Racer® (ammonium nonanoate): Weed control comparisons

Submitted to: Proceedings of Horticultural Industry Show
Publication Type: Proceedings
Publication Acceptance Date: January 18, 2013
Publication Date: N/A

Interpretive Summary: Effective weed control is a major challenge when producing vegetables, and especially difficult with organic vegetable production because there are so few weed control options available to producers. The availability and use of effective post-emergence organic herbicides would increase the likelihood of season-long weed control, reduce crop loses, and decrease the introduction of additional weed seed to the soil. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the effectiveness of potential organic herbicides on weed control. The experiment was conducted without a crop and included two herbicides, AXXE® (65% pelargonic acid) and Racer® (40% ammonium nonanoate). Each herbicide was applied at four rates (1.5, 3, 5, and 10% volume) based on a sprayer volume of 75 gallons per acre. The experiment also included an untreated weedy-check, where the weeds were allowed to grow as a comparison to the herbicide applications. Total, broadleaf, and grass weed control increased as the application rates increased, resulting in a minimum of 89% control 1 day after treatment for the 10% rate for each herbicide. AXXE® provided greater weed control (total, broadleaf, and grass) than Racer® at each similar application rates across the different sampling dates. AXXE® applied at a 5% sprayer volume provided as good or better weed control (total, broadleaf, and grass) than Racer® at a 10% sprayer volume. Yellow nutsedge control for each herbicide was consistently less than the total, broadleaf, and grass control at similar rates. Based on this research, AXXE® provided greater weed control than Racer® and both herbicides would be viable weed control alternates for organic vegetable production.

Technical Abstract: Organic vegetable producers need herbicides that can provide effective season-long weed control. The availability and use of effective post-emergence organic herbicides would increase the likelihood of season-long weed control, reduce crop loses, and decrease the introduction of additional weed seed to the soil. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of broadcast applications of potential organic herbicides on weed control. The experiment was conducted without a crop and included two herbicides, AXXE® (65% pelargonic acid) and Racer® (40% ammonium nonanoate), with broadcast application using 75 gpa, 8004 spray tips, 0.40 gpm, at 4 rates (1.5, 3, 5, and 10% v/v). The experiment also included an untreated weedy-check and 4 replications. Weed control (total, broadleaf, and grass) increased as the application rate increased, resulting in a minimum of 89% weed control 1 DAT for the 10% v/v rate for each herbicide. AXXE® typically provided greater weed control (total, broadleaf, grass, and nutsedge) than Racer® at similar application rates across the different sampling dates. AXXE® applied at 5% v/v provided as good or better weed control (total, broadleaf, grass, and nutsedge) than the 10% v/v rate of Racer®. Yellow nutsedge control for each herbicide was consistently less than the total, broadleaf, and grass control at similar rates, but produced moderate control at the highest application rate (10% v/v). Based on this research, AXXE® provided greater weed control efficacy than Racer® applied at similar product or active ingredient rates, yet both represent potential viable alternate herbicides for organic vegetable production.