ARS | Publication request: Post-directed application of a potential organic herbicide for bell peppers

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: January 24, 2011
Publication Date: August 24, 2011
Citation: Webber III, C.L., Shrefler, J.W., Brandenberger, L.P. 2011. Post-directed application of a potential organic herbicide for bell peppers [abstract]. Proceedings of Southern Weed Science Society. 64:332.

Technical Abstract: Organic pepper (Capsicum annuum L.) producers need appropriate herbicides that can effectively provide post-emergent weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and yields. The experiment included Scythe (registered trademark) (57% pelargonic acid) applied post-directed at 3, 6, and 9% v/v application rates, plus an untreated weedy-check and an untreated weed-free check with 4 replications. Bell pepper, cv. 'Jupiter,' was transplanted on May 28, 2010 into raised 91-cm centered beds. The primary weeds included smooth crabgrass (Digitaria ischaemum (Schreb.) Schreb. ex Muhl.), cutleaf groundcherry (Physalis angulata L.), and spiny amaranth (Amaranthus spinosus L.). Scythe was post-directed applied on June 16 and then reapplied 8 days later (June 25). Smooth crabgrass (55.6%) and cutleaf groundcherry (66.3%) control peaked at 1 day after treatment (DAT) with the 9% application rate. Scythe at 9% v/v rate also resulted in the greatest crop injury at 1 DAT (13.75%). The sequential application of Scythe did not significantly increase grass or broadleaf control. Although weed control and crop yields increased as application rates increased, the less than satisfactory weed control produced significantly lower pepper yields that the weed-free treatment.