Efficacy and Economics of Herbicide Programs Compared to Methyl Bromide for Weed Control in Polyethylene-Mulched Bell Pepper

Abstract

In the absence of an effective alternative to methyl bromide (MeBr), weeds cause a significant economic loss in bell pepper production. A study was conducted to evaluate the efficacy and economics of PRE followed by (fb) POST-directed (POST-DIR) herbicide programs compared with MeBr for weed control in low-density polyethylene (LDPE) mulched bell pepper production. Imazosulfuron at 0.112, 0.224, and 0.336 kg ai ha−1andS-metolachlor at 1.6 kg ai ha−1were PRE-applied fb POST-DIR applied mixture of trifloxysulfuron + halosulfuron at 0.008 and 0.027 kg ai ha−1, respectively, at 4 wk after transplanting (WATP). The standard MeBr treatment (67 and 33% mixture of MeBr + chloropicrin) was applied at 390 kg ai ha−1. In addition, a weed-free (hand weeding) and a non-treated control were used for comparison.S-metolachlor-containing herbicide program controlled Palmer amaranth ≥ 90%, large crabgrass ≥ 78%, and yellow nutsedge ≥ 90%, which were comparable to MeBr. After POST-DIR herbicide application, bell pepper was injured ≥ 17% with theS-metolachlor-containing herbicide program at 6 WATP; however, the crop later recovered. Marketable bell pepper yield in plots treated withS-metolachlor (≥ 29.9 ton ha−1) was comparable to those treated with MeBr. Economic evaluation of the imazosulfuron herbicide programs demonstrated the loss of ≥ $7,300 ha−1. Conversely, theS-metolachlor-containing herbicide program was profitable with a net return of $9,912 ha−1. In addition, theS-metolachlor herbicide program generated a net profit of $173 ha−1compared to the MeBr application. Therefore, PRE-appliedS-metolachlor fb POST-DIR applied trifloxysulfuron + halosulfuron is a potential alternative to MeBr for weed management in LDPE-mulched bell pepper production given the weed spectrum evaluated in this study.