| Plasticulture systems utilizing polyethylene mulch and drip irrigation provide many advantages for tomato and pepper production. However, yellow nutsedge can pierce the polyethylene mulch and compete with the crops for nutrients, water, and sunlight. Greenhouse and field studies were conducted to determine the effect of drip-applied halosulfuron, imazosulfuron, and trifloxysulfuron on yellow nutsedge and solanaceous crops (tomato and pepper). In greenhouse studies, tomato treated with soil applied halosulfuron, imazosulfuron, and trifloxysulfuron had lower visual injury (5, 5, and 14%, respectively) than the POST applied (23, 26, and 54% visual injury, respectively) treatments. Pepper treated in the greenhouse with soil applied halosulfuron, imazosulfuron, and trifloxysulfuron had lower visual injury (8, 6, and 6%, respectively) than POST applied (21, 35, and 26%, respectively) treatments. For both tomato and pepper, injury followed a linear relationship with increasing injury as herbicide rate increased. In field studies, tomato yield (62,722 to 80,328 kg/ha), and height (73 to 77 and 79 to 84 cm at 14 and 21 d after treatment (DAT) was not different among drip applied or POST herbicide treatments. Likewise, pepper fancy grade yield (21,128 to 27974 kg/ha), number one fruit yield (7,825 and 14,672 kg/ha) and pepper height (32 to 37 cm at 14 DAT) were not different among herbicide treatments. In greenhouse studies, photosynthetic rate and stomatal conductance rate of tomato and yellow nutsedge was reduced by soil or POST applied herbicides. Yellow nutsedge control in greenhouse studies by soil applied halosulfuron (78 to 87%), imazosulfuron (69 to 82%), and trifloxysulfuron (85 to 91%) was greater than the nontreated (0%). In field studies, drip applied halosulfuron (72%), imazosulfuron (95%), and trifloxysulfuron (110%) in plasticulture systems had less nutsedge emergence during the experiment than the nontreated (876%). Tomato and pepper have excellent tolerance to halosulfuron, imazosulfuron, and trifloxysulfuron applied through drip irrigation systems. Based on greenhouse and field studies, drip applied herbicides would likely fit into pepper and tomato plasticulture systems and would provide suppression of yellow nutsedge in this system. |
