Toxicity and Site of Uptake of Soil-Applied Imazaquin in Yellow and Purple Nutsedges (<i>Cyperus esculentus</i>and<i>C. rotundus</i>)

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.

Section: Resultssupporting

confidence: 72%

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

McElroy¹,

Yelverton²,

Troxler³

et al. 2003

“…Studies have evaluated yellow nutsedge control with ALS-inhibiting herbicides, including the sulfonylurea (Ackley et al 1996;Derr and Wilcut 1993;Molin et al 1999;Bendixen 1988, 1989), imidazolinone (Ackley et al 1996;Czarnota and Bingham 1997;Derr and Wilcut 1993;Grichar et al 1992;Nandihalli and Bendixen 1988;Richburg et al 1993), triazolopyrimidine sulfonanilide (Askew et al 1999;Nelson and Ren-ner 1998), and pyrimidinyl thiobenzoate (Ackley et al 1996;Wilcut 1999) herbicide families. Several ALS-inhibiting herbicides controlled yellow nutsedge when foliar and soil uptake occurred (Reddy and Bendixen 1989;Richburg et al 1993;Vencill et al 1995;Wilcut 1999).…”

Section: Introductionmentioning

confidence: 99%

Yellow Nutsedge (Cyperus esculentus) Control and Tuber Production with Glyphosate and ALS-Inhibiting Herbicides¹

Nelson

Renner²

2002

Greenhouse and field research evaluated yellow nutsedge growth, vegetative control, and tuber production after application of glyphosate, various acetolactase synthase (ALS)–inhibiting herbicides, and tank mixtures thereof. Yellow nutsedge was controlled by the herbicides halosulfuron at 35 g ai/ha, chlorimuron at 12 g ai/ha, and imazethapyr–imazapyr at 62 g ai/ha (> 70% control); imazethapyr at 70 g ai/ha, glyphosate at 840 g ae/ha, cloransulam at 17.5 g ai/ha, and rimsulfuron at 17.5 g ai/ha (40 to 70% control); and imazamox at 45 g ai/ha (< 40% control). Compared with the untreated control, tuber fresh weight in the field was reduced 45 to 91%, and tuber density was reduced 33 to 90% by all herbicide treatments 42 wk after treatment (WAT) except imazamox and rimsulfuron. Tuber sprouting was reduced to 19% in plots treated with halosulfuron and pyrithiobac compared with untreated yellow nutsedge 42 WAT. Chlorimuron and imazethapyr–imazapyr controlled yellow nutsedge at least 90%, prevented panicle formation, and reduced tuber density and fresh weight by 90% or more 14 WAT in the greenhouse. The addition of glyphosate to cloransulam or imazethapyr increased yellow nutsedge control and reduced tuber density and fresh weight when compared with either ALS-inhibiting herbicide or glyphosate applied alone. Tuber density data indicated that there were 8 tubers for every gram of tubers harvested. Yellow nutsedge height was 15 to 20 cm 4 to 5 wk after tillage, using growth analysis data. Long-term yellow nutsedge management may be aided with treatments that reduce tuber production.

“…Chlorimuron has also been known to significantly reduce dry weight of yellow nutsedge (Nelson and Renner 1998). Imazaquin, although found to be effective POST, is not effective when applied PRE for the control of purple nutsedge (Coats et al 1987), but suppresses yellow nutsedge (Nandihalli and Bendixen 1988). When applied preplant-incorporated, imazaquin controls yellow nutsedge effectively (Askew et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Purple Nutsedge (Cyperus rotundus) and Yellow Nutsedge (Cyperus esculentus) Control in Glyphosate-Tolerant Soybean (Glycine max)¹

Akin¹,

Shaw²

2001

Field studies were conducted to evaluate the effects of glyphosate and conventional herbicides on purple and yellow nutsedges. Tubers collected from the field were counted and tested for viability via growth chamber or triphenyl tetrazolium chloride test to determine the effect of herbicides on tuber density and viability. With purple nutsedge, herbicide treatments containing glyphosate at 0.84 kg/ha followed by (fb) glyphosate at 0.56 kg/ha reduced viable and total tuber density. Among conventional herbicides, treatments containing metolachlor at 2.2 kg/ha plus sulfentrazone at 0.26 kg/ha plus chlorimuron at 0.05 kg/ha applied preemergence (PRE) and metolachlor at 2.2 kg/ha plus imazaquin at 0.14 kg/ha applied PRE fb bentazon at 0.84 kg/ha applied postemergence (POST) reduced total and viable tuber density compared to the nontreated. Metolachlor at 2.2 kg/ha plus sulfentrazone at 0.26 kg/ha plus chlorimuron at 0.05 kg/ha applied PRE fb bentazon applied POST also reduced viable tuber density of purple nutsedge. With yellow nutsedge, all herbicide treatments reduced total and viable tuber density over the nontreated check.