Evaluation of the Use of Preemergence and Postemergence Herbicides Along With Cover Crop Residue for Control of Broadleaf Weeds in Watermelons

Abstract

Field studies were conducted in the spring of 2011 and 2012 at Auburn University research facilities (AURF), Auburn, AL to evaluate the effectiveness of labeled herbicides with the addition of winter cover crops for controlling troublesome escape weed species. Herbicides included ethalfluralin, halosulfuron, carfentrazone, and glufosinate. A total of nine treatments were applied. Treatments included: non-treated (bareground); ethalfluralin at 1.7 lbs a.i./A (PRE) + halosulfuron at 0.048 lb a.i./A (POST); ethalfluralin at 1.7 lbs a.i./A (PRE) + glufosinate at 0.748 lb a.i./A (POST); ethalfluralin at 1.7 lbs a.i./A (PRE) + carfentrazone at 0.031 lb a.i./A (POST); ethalfluralin at 1.7 lbs a.i./A (PRE); halosulfuron at 0.048 lb a.i./A (POST); glufosinate at 0.748 lb a.i./A (POST); carfentrazone at 0.031 lb a.i./A (POST); and cover crop with no herbicide. No differences were seen among treatments containing cover crop residue in 2011 or 2012 when comparing yellow nutsedge populations. In 2011, cover crop residue with ethalfluralin followed by halosulfuron had the highest control of yellow nutsedge. Ethalfluralin followed by carfentrazone had the highest percent of control in 2012. There were no differences between treatments containing cover crop residue when comparing amaranth populations in 2011 or 2012. In 2011, the treatment of cover crop residue with ethalfluralin followed by glufosinate had higher yields than all other treatments except for the treatment of cover crop residue with ethalfluralin followed by carfentrazone. The treatment of cover crop residue with ethalfluralin followed by glufosinate produced more fruit than all other treatments. In 2012, the cover crop and no herbicide treatment was similar in yields to all treatments except the nontreated treatment. Field studies were conducted in the spring of 2011and 2012 at the AURF at Auburn University, AL to evaluate the effectiveness of polyethylene mulch with the addition of winter cover crops for controlling troublesome broadleaf weed species. Four treatments were evaluated. Treatments included: black polyethylene mulch on bare soil; rye/clover cover crop with no polyethylene mulch; cover crop tilled into soil covered with polyethylene mulch, and polyethylene mulch with rye not tilled in. This was a completely randomized block design study with four replications of each treatment. Data were collected to determine which treatment exhibits the greatest weed control. Differences were observed in both 2011 and 2012 when comparing yellow nutsedge populations. In 2011, the plastic mulch and cover crop tilled into the soil treatment had fewer nutsedge than the treatment with cover crop residue without plastic mulch. In 2012, all treatments containing plastic mulch had lower yellow nutsedge per square yard than the cover crop residue alone treatment. No differences were observed when comparing amaranth populations in 2011 or 2012. In 2011and 2012, treatments containing plastic mulch on bare soil and plastic mulch on cover crop residue produced higher yields than the cover crop alone treatment. In both years, all treatments containing plastic mulch were comparable and were different from the treatment with cover crop residue alone.