Influence of Simulated Quinclorac Drift on the Accumulation and Movement of Herbicide in Tomato (Lycopersicon esculentum) Plants

Quinclorac (3,7-dichloro-B-quinolinecarboxylic acid) is a herbicide commonly used in rice, and its drift has been suspected of causing injury to off-target tomato fields throughout Arkansas. Studies were conducted to evaluate the effects of single and multiple simulated quinclorac drift applications on tomato plant growth and development. Residues extracted from tomato plants treated with 0.42 g of ai ha(-1) were below the detection limit of liquid chromatography-double mass spectrometry (LC-MS/MS) analysis. Quinclorac residue levels and half-lives in tomato tissue increased as the application rate and number of applications increased. From 3 to 72 h after C-14-quinclorac treatment of plants, most of the absorbed C-14 was retained in the treated leaf, and translocations of C-14 out of the treated leaf of vegetative and flowering tomato plant tissues were similar. Of the C-14 that translocated out of the treated leaf, the greatest movement was acropetally. The flower cluster contained 1% of the total absorbed C-14, which suggests the potential for quinclorac translocation into tomato fruit. More extensive research will be required to understand the impact that quinclorac may have on tomato production in the area.