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. 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. 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. The maximum concentration of imidacloprid detected in run-off water was 0.49 mg litre−1 and occurred during the first run-off event.

Source: Kevin L Armbrust, Harold B Peeler (2002) Pest Management Science 58, 702-706