Toxicity, Absorption, and Translocation of Soil-Applied Chlorimuron in Yellow and Purple Nutsedge (Cyperus esculentusandC. rotundus)

Abstract

The activity of soil-applied chlorimuron in yellow and purple nutsedge was studied in greenhouse and laboratory experiments. Soil-applied chlorimuron decreased tuber sprouting by 80% in yellow nutsedge and by 30% in purple nutsedge at 60 g ai/ha. Chlorimuron decreased shoot emergence by 53 to 83% and shoot growth by 85 to 99% in both species at rates as low as 10 g/ha. Previous exposure of tubers to chlorimuron-treated soil reduced tuber resprouting by 20 to 25% in herbicide-free soil at 60 g/ha in both species. There was no rate response in shoot emergence from tubers previously exposed to chlorimuron, but shoot dry weight decreased by 60 to 81% in both species at 60 g/ha. At 12 h after application, 47% of the total14C applied to the shoot in yellow nutsedge and 32% of that applied in purple nutsedge were absorbed. However, less than 1% of the total14C applied was translocated out of the shoot and into the roots and tuber in either species. In both species, 1.3% of the14C applied to the roots and tuber was absorbed and 0.1% was translocated out of the roots and tuber into the shoot at 12 h after application. The pattern of root- and tuber-absorbed14C distribution indicated that the14C absorbed by the tuber remained in the tuber and that absorbed by the roots was translocated to the shoots.

Effect of MON 12037 on the Growth and Tuber Viability of Purple Nutsedge (Cyperus rotundus)

“…In greenhouse studies using purple nutsedge grown in pots, significant reductions in shoot and root tuber growth and in shoot regrowth were obtained with foliar applications of rmazaquin { (t)-2-14,5-dihydro-4-methyl-4 -(1methy lethyl ) -5o x o -L H -rmrdazol-Z -yl I -3qui no linecarboxylic acid) (Derr and Wilcut 1993;Nandihalli and Bendixen 1988a), imazethapyr { (I)-2-14,5-dihydro-4 -methyl-4 -( 1methy I ethy I ) -5o x o -I Htmrdazol-2 -yll -5ethyl-3-pyridinecarbolilic acid) (Richburg et al 1993), AC 263,222 { ( t )-2-14,5 -dihydro -4-methyl-4-( 1methy lethy 1 ) -5o x o -I H -rmrdazol-Z -yI)-5me thy I -3p yri dinecarboxylic acid) (Richburg et al 1994), MON 12037 (Vencill et al 1995), and soil applications of chlorimuron (Reddy and Bendixen 1989). These results demonstrate that when applied to young, actively growing plants, excellent control was achieved and regrowth was prevented.…”

“…Imazaquin and chlorimuron were adsorbed by the roots and shoots of both yellow and purple nutsedges and were translocated both acropetally and basipetally (Nandihalli and Bendixen 1988a, I988b;Reddy and Bendixen 1989). However, less than IVo of foliar-applied 'aC-herbicide was translocated to the roots or tubers in either case.…”

Effects of isothiocyanates on purple (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.)

“…In addition to the competitive attributes of purple and yellow nutsedge, they are difficult to control because of dormant tubers (Keeley & Thullen 1974; Reddy & Bendixen 1989; Santos et al . 1997).…”

“…In addition to the competitive attributes of purple and yellow nutsedge, they are difficult to control because of dormant tubers (Keeley & Thullen 1974;Reddy & Bendixen 1989;Santos et al 1997). A single plant of purple nutsedge can produce > 200 tubers in 4 months under favorable environmental conditions (Jordan-Molero & Stoller 1978).…”

Uptake and efflux of chlorimuron ethyl by excised soybean (Glycine max (L.) Merr.) root tissue†

“…Chlorimuron ethyl, a member of the sulfonylurea herbicides, is used for broad-spectrum weed control in soybean crops (Ploeg et al, 1984). Chlorimuron ethyl is taken up by both roots and foliage of treated plants (Reddy & Bendixen, 1988;Reddy & Bendixen, 1989). This herbicide kills plants by inhibiting acetolactate synthase (Ray, 1986), an enzyme required for biosynthesis of the essential amino acids, valine and isoleucine.…”