Fluctuations over Time in Dislodgeable 2,4-D Residues from Hybrid Bermudagrass Athletic Fields.

Research to date has confirmed 2,4-D residues may dislodge from turfgrass in residential settings; however, knowledge pertaining to 2,4-D residues on hybrid bermudagrass (Cynodon dactylon L. x C. transvaalensis) athletic fields is limited.  Moreover, previous 2,4-D residue research has been nondescript regarding sample time within a d (TWD) or conducted in the afternoon when the turfgrass canopy is dry, potentially underestimating dislodgement.  Field research was conducted to quantify dislodgeable 2,4-D residues at varying TWD (5:00, 7:00, 9:00, 11:00 or 13:00) over several d after treatment (DAT; 1, 2, 3, 6 or 12).  Data suggest 2,4-D dislodgeability decreased as TWD increased, with < 0.1% of the applied dislodged at all 13:00 sample timings.  Further, increasing dislodgeable residues from afternoon to the subsequent morning suggests 2,4-D can re-suspend over night on treated turfgrass vegetation up to 3 DAT.  This response was attributed in part to non-precipitation climatic conditions favoring turfgrass canopy wetness.  Findings from this research will improve turfgrass management practices and research designed to assess and minimize human pesticide exposure.