Selective Exposure of Yellow (Cyperus esculentus) and Purple Nutsedge (Cyperus rotundus) to Postemergence Treatments of CGA-362622, Imazaquin, and MSMA1

Greenhouse studies were conducted to evaluate shoot number, shoot weight, and root weight reduction of yellow and purple nutsedge to three placement levels (soil, foliar, and soil + foliar applied) and four herbicide treatments (CGA-362622, imazaquin, MSMA, and imazaquin + MSMA). Soil-applied CGA-362622 reduced shoot number, shoot weight, and root weight greater than foliar-applied CGA-362622. Foliar-applied imazaquin and soil-applied MSMA achieved little reduction in measured variables compared with the nontreated control. Foliar-applied imazaquin and soil-applied MSMA reduced shoot number, shoot weight, and root weight less than imazaquin + MSMA applied in a similar manner. Averaged over placement levels, imazaquin reduced shoot weight of yellow nutsedge greater than purple nutsedge. Averaged over herbicide treatments, soil-applied treatments were more effective in reducing purple nutsedge shoot number, whereas foliar-applied treatments were more effective in reducing yellow nutsedge shoot number. Nomenclature: CGA-362622, N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluroethoxy)-pyridin-2-sulfonamide sodium salt; imazaquin; MSMA; purple nutsedge, Cyperus rotundus L. #3 CYPRO; yellow nutsedge, Cyperus esculentus L. # CYPES. Additional index words: Foliar absorption, root absorption. Abbreviations: DAP, days after planting; DAT, days after treatment; NIS, nonionic surfactant; POST, postemergence.