Season-Long Interference of Yellow Nutsedge (Cyperus esculentus) with Polyethylene-Mulched Bell Pepper (Capsicum annuum)

Yellow nutsedge, a weed commonly present in Florida vegetable fields, may substantially reduce crop yields when not controlled. Soil fumigation with methyl bromide effectively controls nutsedges, but methyl bromide is being phased out of production and use in the United States. Therefore, nutsedge management in bell pepper is a cause for concern. An experiment was conducted during four seasons (spring and fall of 1999 and 2000) to determine the tolerance of bell pepper grown at two in-row spacings (23 and 31 cm) to interference resulting from planted yellow nutsedge tuber densities (0 to 120$\text{tubers}/{\rm m}^{2}$). Relative to yields with no nutsedge, pepper fruit yields in each season were reduced 10% with fewer than 5 planted$\text{tubers}/{\rm m}^{2}$. Yield losses increased more rapidly with an increase in initial nutsedge density from 0 to 30 than from 30 to 120$\text{tubers}/{\rm m}^{2}$. With 30 nutsedge$\text{tubers}/{\rm m}^{2}$, large fruit yield was reduced 54 to 74% compared to that with no nutsedge. Nutsedge shoots overtopped the pepper plants as early as 6 wk after treatment when, with 15 planted$\text{tubers}/{\rm m}^{2}$, nutsedge interference reduced pepper plant biomass by 10 to 47%. In the absence of methyl bromide, weed control strategies with high efficacy against yellow nutsedge will be needed for bell pepper production.