An evaluation of preemergence herbicides for control of prostrate spurge (Euphorbia supina Raf.) in container nursery production of low water use landscape plants in the Desert Southwest

Abstract

Five preemergent herbicides were evaluated for control of prostrate spurge (Euphorbia supina Raf.) in seven container-grown arid landscape ornamentals at the following rates in kilograms active ingredient per hectare: oxyfluorfen, 0.6, 1.1 and 2.0; oryzalin, 3.0, 6.0 and 12.0; Dacthal, 22.4, 44.8 and 89.7; norea, 1.2, 2.2 and 4.5; and axadiazon, 2.2, 4.5 and 9.0, respectively. Prostrate spurge reaches its peak in summer. During the first test, February 5 - May 20, 1981, or 104 days, all herbicides provided satisfactory to complete control at all rates, except norea at 1.2 and 2.2 and oxadiazon at 2.2 were ineffective in one test species. During the second test, May 21 - August 17, 1981 or 88 days, oryzalin gave the best overall control; oxyfluorfen provided effective control only at 2.2; oxadiazon produced erratic results; and norea and Dacthal became ineffective at all rates after 23 days. No phytotoxicity to the plants was observed.