Assessing Predator Activity on Clay Models in Response to Common Insecticides in Turfgrass

Pest management in turfgrass is primarily driven by organophosphates, neonicotinoids, pyrethroids, diamides, and insect growth regulators. The impact of these commonly used insecticides on predatory activity is inadequately documented, even though predator densities are widely studied. Predatory activity is quantified by analyzing the type and density of impressions left on the clay models. Thus, the objective was to determine the effects of insecticide on predatory activity by examining impression types and density on clay models in insecticide‐treated turfgrass. The insecticides bifenthrin, acephate + imidacloprid, imidacloprid, chlorantraniliprole, tetraniliprole, methoxyfenozide, and novaluron were applied to bermudagrass, and clay models were deployed over time to assess arthropod activity in two trials. Across trials 1 and 2, insecticides had clear but time‐dependent effects on impressions created by predators. Early significant reductions in total impressions were observed for bifenthrin in trial 1 and for acephate + imidacloprid, chlorantraniliprole, and imidacloprid in trial 2 compared to the water treatment; however, these effects did not differ significantly during the mid‐period. In the later period, significant reductions in total impressions re‐emerged, most consistently with bifenthrin and tetraniliprole, with acephate + imidacloprid also demonstrating reductions in impressions on models in trial 2. Paired marks exhibited similar temporal dynamics, further indicating their sensitivity to treatment effects. In contrast, prick, fragment, and dent impressions were unaffected by insecticide treatments, whereas scratch impressions showed variable responses across treatments, with no consistent pattern.