Purple Nutsedge Density Research Articles

Purple Nutsedge (Cyperus rotundus) Management in Corn (Zea mays) and Cotton (Gossypium hirsutum) Rotations

A field study was conducted in 1994 and 1995 to determine the effect of MON 12037, linuron, and ametryn on purple nutsedge density in field corn in a 2-yr rotation with cotton. Each corn treatment included cultivation and noncultivation. A standard treatment for purple nutsedge control was applied to all cotton plots in the second season of the corn–cotton rotation. Purple nutsedge shoot densities were reduced in cultivated MON 12037, noncultivated MON 12037, and cultivated ametryn in the corn–corn and corn–cotton rotations. Purple nutsedge tuber population was reduced in the corn–corn rotation by MON 12037 with and without cultivation, cultivated linuron, and cultivated ametryn treatments relative to the noncultivated check. In the corn–cotton rotation, purple nutsedge tuber population was reduced only by the cultivated MON 12037 and cultivated ametryn treatments relative to the noncultivated check.

Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on the Growth of Transplants of Three Papaya (Carica papaya) Cultivars

Nursery experiments were conducted in Santo Domingo, Dominican Republic, to determine the effect of increasing population densities of purple nutsedge (Cyperus rotundus) on the growth of papaya (Carica papaya) transplants. Seeds of `Sunrise Solo', `Red Lady', and `Cartagena Ombligua' were separately sown in plastic 12 × 15-cm containers filled with a 1:1 mixture of sand and loamy soil. Viable purple nutsedge tubers were planted 5 cm apart from the papaya seeds. The purple nutsedge initial population densities were 0, 1, 2, 4, and 6 tubers per container. The crop and the weed were sown the same day and allowed to interfere during 6 weeks. Purple nutsedge density had a significant effect on the height, leaf area, and shoot dry weight of the three papaya cultivars. There was no significant difference in the response of the three papaya cultivars to purple nutsedge densities. In general, as purple nutsedge density increased, papaya growth decreased. Nutsedge interference caused papaya shoot dry weight losses of 15% at the density of one plant per container and 73% at six plants per container.

Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on the Yield of Eggplant (Solanum melongena)

Field experiments were conducted in Santo Domingo, Dominican Republic, to determine the effect of increasing population densities of purple nutsedge (Cyperus rotundus) on the yield of eggplant (Solanum melongena). Purple nutsedge populations were established by transplanting viable tubers on 1-m-wide soil beds previously fumigated to suppress volunteer weeds. Nutsedge densities were 0, 50, 100, 150, and 200 plants (tubers) per m2. `Jira' eggplants and purple nutsedge were transplanted the same day and were allowed to interfere season-long. Purple nutsedge initial population densities of up to 100 plants per m2 did not significantly affect the fruit yield of `Jira' eggplants. However, nutsedge densities between 100 and 200 plants per m2 had a significant impact on eggplant yield, causing a linear decline in fruit yield as purple nutsedge density increased. Eggplant fruit yield loss was 22.3% at the density of 200 nutsedge plants per m2.