Critical yellow nutsedge-free period for polyethylene-mulched bell pepper

Abstract

Yellow nutsedge (Cyperus esculentus L.) interference with bell pepper (Capsicum annuum L.) has become an important concern because of the phase-out of methyl bromide as a soil fumigant. The critical period for yellow nutsedge control in pepper was determined in two adjacent experiments (removal and plant-back) conducted twice in separate fields each Spring and Fall 2000 in Gainesville, Fla. In the removal experiment, nutsedge was planted with pepper in all but the full-season (13 weeks) weed-free controls and removed at 1,3,5, and 7 weeks after pepper transplanting (WAPT). Full-season weedy control plots in the removal experiment were obtained by never removing nutsedge planted with pepper (0 WAPT). In the plant-back experiment, all but the full-season weed-free controls received nutsedge with nutsedge planted at 0 (full-season weedy control), 1,3,5, and 7 WAPT. Sprouted nutsedge tubers were planted at a density of 45 tubers/m2. Results indicated that a nutsedge-free period from 3 to 5 WAPT in spring and 1 to 7 WAPT would prevent >10% yield reductions of large and marketable peppers. Full-season nutsedge interference reduced pepper yields by >70%. When planted with pepper, nutsedge shoots grew taller than pepper plants with nutsedge heights at 5 WAPT up to two times greater in fall than spring. Results indicated that yellow nutsedge control practices should be initiated earlier and continue longer in fall than spring due to faster early-season nutsedge growth in fall than spring.