Abstract
The effects of mixed populations of purple and yellow nutsedges (Cyperus rotundus L. and C. esculentus L.) on the growth and yield of eggplant (Solanum melongena L.) were studied in field experiments conducted in Florida. Tubers of purple and yellow nutsedges were planted onto the eggplant soil beds at a fixed density of 60 plants/m and were allowed to grow alongside the crop season-long. The percentages of yellow nutsedge:purple nutsedge in the mixed stands were 0:100 (pure purple nutsedge stand), 25:75, 50:50, 75:25, and 100:0 (pure yellow nutsedge stand). Eggplant shoot dry weight, leaf area, concentration of nitrogen in nitrate and potassium in leaf petiole sap, and fruit yield decreased as the number of yellow nutsedge plants in the mixed nutsedge stands increased. Tuber productivity, and thus the potential for high nutsedge population densities in the following season, was higher in yellow nutsedge than in purple nutsedge. This results indicate that the percentage of yellow nutsedge in a mixed stand of purple and yellow nutsedges may significantly influence the growth and yield of eggplant, and that it may be more important to suppress yellow nutsedge than purple nutsedge.
