Effects of formulation on the run-off of imidacloprid from turf.
Imidacloprid is a pesticide often used to control insect pests on residential lawns and golf courses. To investigate its potential to be transported into non-target aquatic systems by rainfall events, imidacloprid was applied as 5.0 g kg-1 GR and 750 g kg-1 WP to 12 plots planted with bermuda grass set on a 5% slope. The dimethylamine salt of the herbicide 2,4-D was applied simultaneously to the plots in order to normalize the results to prior trials conducted with other pesticides. At a rate of 2.5 cm h-1, 5-cm rainfall events were simulated at 24 and 48 h after application and 2.5-cm events were simulated at 96 and 192 h. After each event water was collected from each plot and analyzed by HPLC for residual insecticide or herbicide. Approximately 1.4% of the insecticide formulated as WP and 1.9% of that formulated as GR was lost from the plots after four run-off events. Of the total mass lost, 64% and 30% respectively occurred in the first and second run-off events for the WP formulation versus 75% and 20% for the GR formulation. These values compare with a total mass export of 2.6% for 2,4-D, of which 95% and 4% of the loss occurred respectively in the first and second run-off events. The maximum concentration of imidacloprid detected in run-off water was 0.49 mg litre-1 and occurred during the first run-off event.
Armbrust
Kevin L
KL
University of Georgia-Georgia Station, 1109 Experiment St, Griffin, GA 30223, USA. armbrust@ra.msstate.edu
Peeler
Harold B
HB
D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D004787:Environmental Pollution / Q000032:analysis*; D007093:Imidazoles / Q000032:analysis* / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis* / Q000737:chemistry*; D015394:Molecular Structure; D000073943:Neonicotinoids; D009574:Nitro Compounds; D006109:Poaceae; D012987:Soil; D013997:Time Factors; D014867:Water; D014876:Water Pollution / Q000032:analysis
D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D012987:Soil; D014867:Water; D015084:2,4-Dichlorophenoxyacetic Acid; C082359:imidacloprid