Field crop growers in the United States have adopted prophylactic pest management strategies to control sporadic crop pests that are spatially and temporally difficult to predict. While evidence shows these preventative management practices, specifically pesticidal seed treatments, can be important in regions with predictable pest pressures, employing them ubiquitously in field crops across the northeastern U.S. can have variable returns on productivity. Further, prophylactics may also limit the potential of integrated pest management (IPM). A three-year field experiment (2017–2019) was conducted in a maize-soybean cropping system to compare the influence of a preventative pest management practice and a scouting-based IPM practice on biological control organisms. Aboveground predator densities were measured via pitfall trapping and predation temporal dynamics were assessed using a standard sentinel-bait assay at two time points per year. Belowground biological control potential was determined using a sentinel-bait bioassay to quantify the abundance of soil-borne entomopathogenic fungi (EPF). The variable responses of beneficial communities to pesticide inputs were strongly influenced by season and time of application, underscoring the importance of applying pesticides only when necessary. Compared with no pesticide use, pesticidal seed treatments and foliar sprays together in a maize-soybean production system suppressed total predator activity-density, spider activity-density, predation, and infection potential of soil-borne entomopathogenic fungi in one out of three years of the field study. In the third year, the activity-density of spiders increased across all fields in preventative plots that included seed treatments only. Overall, the use of pesticides did not improve crop yield in either maize or soybean. These findings highlight that the use of a prophylactic pesticide program may not always be necessary for maximum crop productivity and that this management approach can occasionally have unintended negative consequences on above- and belowground soil biota and the ecosystem services they provide.

美国的大田作物种植者已采用预防性害虫管理策略来控制在空间和时间上难以预测的散发性作物害虫。虽然有证据表明这些预防性管理实践，特别是杀虫种子处理，在可预测虫害压力的地区可能很重要，但在美国东北部的大田作物中普遍采用它们可以产生可变的生产力回报。此外，预防措施也可能限制综合虫害管理 (IPM) 的潜力。在玉米 - 大豆种植系统中进行了为期三年的田间试验（2017-2019），以比较预防性害虫管理实践和基于侦察的 IPM 实践对生物控制生物的影响。地上捕食者密度通过陷阱捕获测量，捕食时间动态通过标准哨兵诱饵分析在每年的两个时间点进行评估。使用哨兵诱饵生物测定来量化土壤传播的昆虫病原真菌 (EPF) 的丰度来确定地下生物控制潜力。有益社区对农药投入的不同反应受季节和施用时间的强烈影响，强调了仅在必要时施用农药的重要性。与不使用农药相比，在玉米 - 大豆生产系统中，农药种子处理和叶面喷洒在三年中的一年内抑制了土壤传播昆虫病原真菌的总捕食者活动密度、蜘蛛活动密度、捕食和感染潜力。实地研究。在第三年，在仅包括种子处理的预防性地块中，所有田地中蜘蛛的活动密度都增加了。总体而言，使用杀虫剂并没有提高玉米或大豆的作物产量。这些发现强调，预防性杀虫剂计划的使用可能并不总是为了最大限度地提高作物生产力，而且这种管理方法有时会对地上和地下土壤生物群及其提供的生态系统服务产生意想不到的负面影响。