Soil ecological responses to pest management in golf turf vary with management intensity, pesticide identity, and application program

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Abstract While the unintended effects of pesticide applications in agroecosystems have received much attention, the consequence of different pest management strategies for beneficial soil biota in managed grass ecosystems remains poorly documented. In this study, we investigated the responses of major soil biological traits to both the short- and long-term effects of pesticide inputs in golf turfgrass. Overall, golf course fairways receiving regular, high-rate pesticide inputs exhibited suppression in soil biological traits involved in litter decomposition/nutrient mineralization (decomposer arthropod abundance and acid phosphatase activity), and plant nutrient uptake/plant protection (mycorrhizal fungi). In contrast, most beneficial soil biota appeared to tolerate a low level of pesticide input. In a short-term manipulative experiment we observed that monthly applications of chlorothalonil and a single application of imidacloprid, both at a medium label rate, consistently suppressed decomposer microarthropods over a 4-month period. The imidacloprid application also reduced the total infection of mycorrhizae and dark septate endophytes in roots. These results suggest that the use of pesticides as a whole does not always result in negative impacts on soil biota, but rather that the pesticide effects vary among functional groups of soil biota and are contingent upon long-term patterns of pesticide input intensity, and short-term differences in active ingredient and application program (application rate and frequency). These findings highlight opportunities for optimizing management practices to achieve pest management goals without compromising soil ecosystem services.