Toxicity, Absorption, Translocation, and Metabolism of 2,4-D in Yellow Nutsedge

Abstract

We sprayed yellow nutsedge (Cyperus esculentus L.) with 0.56, 1.12, and 2.24 kg/ha of (2,4-dichlorophenoxy)acetic acid (2,4-D) at the two and four-leaf stages in both field and growth chamber studies. Compared to non-treated plants, these rates significantly reduced shoot weight, rhizome weight, and rhizome number 12 days after application. There were no significant differences in these growth responses among the rates tested, when applied one, two, and three times at consecutive 12-day intervals. We pretreated two and four-leaf plants with 0.56, 1.12, and 2.24 kg/ha of 2,4-D immediately before foliar application of 14C-2,4-D. The increase in pretreatment rates decreased the percentage of the applied radioactivity which was absorbed and translocated. Of the radioactivity absorbed, a rather constant percentage translocated from the treated area in the different treatments. The radioactivity translocated from the application site for at least 288 hr after treatment. Less than 19% of the 14C-2,4-D applied was absorbed into the leaves 24 hr after application. Ninety-eight to 100% of the methanol-soluble radioactivity that translocated to developing leaves, rhizomes, and roots chromatographed identically to 14C-2,4-D.

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

“…Successful con trol of nutsedge with foliar herbicides requires transloca tion of the active ingredient to the meristematic cells of the rhizome apex, basal bulb, and tuber buds (5,10,22,23). As in other plants, movement of foliar-applied herbi cides in nutsedge species is governed by the relative activity of "source" and ''sink" (1,5,12,17). While high concentrations of herbicides are lethal, sub lethal doses may have other growth regulatory effects, espe cially on perennial plants (8).…”

Yellow Nutsedge Control in Landscape Plants

“…Postemergence control of yellow nutsedge with chlorimuron and imazaquin was equivalent to, or better than, that with bentazon and glyphosate. Successful yellow nutsedge control with foliar-applied herbicides requires rapid absorption and translocation of the active ingredient to the meristematic cells of the basal bulb, rhizome apices, and tubers in sufficient quantities to kill the entire plant (Bhan et al, 1970;Hauser, 1963;Sprankle et al, 1975;Wills and Briscoe, 1970;Wills et al, 1980). Bentazon control of yellow nutsedge is often restricted due to the absence of basipetal translocation to parent tubers and very little acropetal translocation to other plant parts (Stoner et al, 1975).…”

Experiments with Cyperus rotundus L. II. Effects of some herbicides and growth regulators

“…In Experiment 7,2,4-D evidently caused some death and decay of tubers and in several experiments reduced the percentage germination of recovered tubers; the difference may lie in the quantity of 2,4-D reaching the tubers. Bhan et al (1970) showed that translocation of 2,4-D could continue for more than 12 days. Drenching tubers in vermicuiite with 2,4-D solution totally prevented any germination, though no outward signs of decay were evident 35 days later (Hammerton, 1974b) and injection of 2,4-D ester into infested soil gave a high level of kill with very few shoots appearing over 8 weeks (Hammerton, unpublished data).…”

“…2,4-D can be very effective for field control of nutgrass (Burgis, 1969;Bajpai & Porwal, 1971). The effects on shoot number, underground and tuber dry weight support those of Bhan, Stoller & Slife (1970) with C. esculentus. An earlier trial (Hammerton, 1974a) showed 2,4-D to have only a temporary effect on new tuber number and dry weight and on rhizome dry weight: after an initial reduction there was a steady increase in these parameters.…”