Published online by Cambridge University Press: 12 June 2017
Optimum conditions for leafy spurge control with sulfometuron were determined. Absorption and translocation of 14C-sulfometuron to roots in leafy spurge averaged 11 and 0.1% of applied herbicide, respectively, and were not affected by growth stage. Absorption and translocation increased to 40 and 4%, respectively, of applied 14C-sulfometuron when the relative humidity remained at 90 and 95% for at least 72 h after treatment Absorption and translocation of 14C-sulfometuron to the roots were similar at 18/14 and 24/20 C and when 14C-sulfometuron was applied with picloram or 2,4-D. Absorption of 14C-picloram was greater but 14C-2,4-D absorption was less when applied with sulfometuron compared to picloram or 2,4-D applied alone. Sulfometuron plus picloram applied during the fall regrowth stage provided better leafy spurge control than either herbicide applied alone. The combination treatment would be useful especially in areas where grass injury was acceptable in order to extend the fall treatment season by 2 to 3 wk compared to present practices.