G. L. Lamoureux, D. Rusness
Nov 1, 1995
Citations
1
Influential Citations
32
Citations
Journal
Pesticide Biochemistry and Physiology
Abstract
Abstract Quinclorac is a herbicide registered in the United States for use in rice. In this study, the uptake, metabolism, translocation, and toxicity of quinclorac were evaluated for the suitability of this herbicide for use in the control of leafy spurge. [ 14 C]Quinclorac in the presence of a surfactant was readily absorbed through the leaves of leafy spurge. Alter foliar application, ca. 20% of the quinclorac became sequestered in the treated leaves. The remainder of the quinclorac was translocated basipetally and acropetally. The young leaves and apex were the strongest sinks for quinclorac. Although quinclorac was translocated to the roots, it was effluxed rapidly from the roots into the soil. Quinclorac was also taken up by the roots and translocated acropetally. it was metabolized to a C-1 glucose ester that was converted subsequently to a pentosylglucose ester (major product) or a malonylglucose eater (minor product). Quinclorac was metabolized at a rate of 1 nmol/g tissue/hr in the young leaves. Quinclorac was toxic to leafy spurge when applied to the leaves (LD 50 2.0 kg/ha), the soil (LD 50 1.7 kg/ha), or to both the leaves and the soil (LD 50 1.0 kg/ha). The activity of soil-applied quinclorac was increased 24-fold when the shoots were cut off at the soil level prior to treatment (LD 50 0.07 kg/ha). Symptoms were typical of an auxenic herbicide.