Behavior of14C-Haloxyfop in Common Bermudagrass (Cynodon dactylon) Stolons

Abstract

The behavior of the methyl ester of14C-haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} in common bermudagrass [Cynodon dactylon(L.) Pers. # CYNDA] stolons was examined in greenhouse experiments at two different seasons. The14C from the herbicide applied on the leaves of a stolon node translocated no more than 3% of the applied radioactivity to the apex and base. Movement out of stolons was not significant. In early summer less than 1% translocated in each direction; in early fall more than 2% moved to the apex and less than 1% toward the base. Decrease of14C recovery with time was evident in both seasons, particularly in early summer. Haloxyfop volatilization from the leaf surface apparently plays a significant role in recovery decrease. The14C found in stolons in early summer was approximately the same as that of early fall, although herbicide remaining available for uptake on the leaf surface was lower in the former season. We suggest that environmental conditions that favor volatilization could enhance uptake.