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United States Department of Agriculture

Agricultural Research Service

Research Project: ORGANIC AND REDUCED INPUT FRESH MARKET SPECIALTY CROP PRODUCTION SYSTEMS FOR THE SOUTHERN GREAT PLAINS Title: Over-the-top broadcast applications of ammonium nonanoate on onion weed control, crop injury, and yields

item Webber, Charles
item Shrefler, James -
item Brandenberger, Lynn -

Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2010
Publication Date: August 30, 2011
Citation: Webber III, C.L., Shrefler, J., Brandenberger, L.P. 2011. Over-the-top broadcast applications of ammonium nonanoate on onion weed control, crop injury, and yields [abstract]. National Allium Research Conference, December 8-10, 2010, Reno, Nevada. Available:

Technical Abstract: Racer (registered trademark) (40% ammonium nonanoate) is a potential herbicide for organically grown food crops. Ammonium nonanoate occurs in nature and is primarily formed from biodegradation of higher fatty acids. Research was conducted in southeast Oklahoma to determine the effect of application rates and broadcast application of Racer on weed control efficacy, crop injury, and yields. Intermediate day, sweet onions, cvs. ‘Candy,’ and ‘Cimarron,’ were transplanted on March 20, 2009. The experiment included 8 weed control treatments (3 application rates at 2 hand-weeding levels, plus an untreated weedy-check and an untreated weed-free check) with 4 replications. Broadcast applications of Racer at 7.5 resulted in poor (70% or less) broadleaf weed control, while Racer at 10 and 15% provided excellent (equal to or greater than 90%) total broadleaf weed control through 10 DAT. Onion injury increased as Racer application rate increased with no significant difference in injury ratings among treatments at 18 DAT. Crop injury and lack of weed control from Racer reduced crop yields compared to the untreated weedy-check. If the Racer’s application method can be modified to reduce crop injury, the higher application rate has potential to make significant impact on broadleaf weed control in spring-transplanted onions.

Last Modified: 8/27/2015
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