Hung Keng-Lou James, Ternest John J, Wood Thomas J, Ingwell Laura L, Bloom Elias H, Szendrei Zsofia, Kaplan Ian, Goodell Karen
Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Newark, OH, USA.
Oklahoma Biological Survey, School of Biological Sciences, University of Oklahoma, Norman, OK, USA.
J Econ Entomol. 2025 Feb 11;118(1):262-273. doi: 10.1093/jee/toae202.
Controlling crop pests while conserving pollinators is challenging, particularly when prophylactically applying broad-spectrum, systemic insecticides such as neonicotinoids. Systemic insecticides are often used in conventional agriculture in commercial settings, but the conditions that optimally balance pest management and pollination are poorly understood. We investigated how insecticide application strategies control pests and expose pollinators to insecticides with an observational study of cucurbit crops in the Midwestern United States. To define the window of protection and potential pollinator exposure resulting from alternative insecticide application strategies, we surveyed 62 farms cultivating cucumber, watermelon, or pumpkin across 2 yr. We evaluated insecticide regimes, abundance of striped and spotted cucumber beetles (Acalymma vittatum [Fabricius] and Diabrotica undecimpunctata Mannerheim), and insecticide residues in leaves, pollen, and nectar. We found that growers used neonicotinoids (thiamethoxam and imidacloprid) at planting in all cucumber and pumpkin and approximately half of watermelon farms. In cucumber, foliar thiamethoxam levels were orders of magnitude higher than the other crops, excluding nearly all beetles from fields. In watermelon and pumpkin, neonicotinoids applied at planting resulted in 4-8 wk of protection before beetle populations increased. Floral insecticide concentrations correlated strongly with foliar concentrations across all crops, resulting in high potential exposure to pollinators in cucumber and low-moderate exposure in pumpkin and watermelon. Thus, the highest-input insecticide regimes maintained cucumber beetles far below economic thresholds while also exposing pollinators to the highest pollen and nectar insecticide concentrations. In cucurbits, reducing pesticide inputs will likely better balance crop protection and pollination, reduce costs, and improve yields.
在保护传粉者的同时控制农作物害虫具有挑战性，尤其是在预防性施用广谱性、内吸性杀虫剂（如吡虫啉类）时。内吸性杀虫剂常用于商业环境中的传统农业，但能最佳平衡害虫管理和授粉的条件却鲜为人知。我们通过对美国中西部葫芦科作物的观察性研究，调查了杀虫剂施用策略如何控制害虫以及使传粉者接触杀虫剂的情况。为了确定替代杀虫剂施用策略所带来的保护期和传粉者潜在接触情况，我们在两年内对62个种植黄瓜、西瓜或南瓜的农场进行了调查。我们评估了杀虫剂使用方案、条纹黄瓜甲虫和斑点黄瓜甲虫（Acalymma vittatum [Fabricius] 和 Diabrotica undecimpunctata Mannerheim）的数量，以及叶片、花粉和花蜜中的杀虫剂残留。我们发现，所有黄瓜和南瓜种植场以及约一半西瓜种植场的种植者在种植时使用了吡虫啉类（噻虫嗪和吡虫啉）。在黄瓜中，叶面噻虫嗪水平比其他作物高出几个数量级，几乎将所有甲虫排除在田间。在西瓜和南瓜中，种植时施用的吡虫啉类在甲虫数量增加前提供了4 - 8周的保护。所有作物的花中杀虫剂浓度与叶面浓度密切相关，导致黄瓜中的传粉者有很高的潜在接触风险，而南瓜和西瓜中的接触风险为低至中等。因此，投入最高的杀虫剂使用方案将黄瓜甲虫数量维持在远低于经济阈值的水平，同时也使传粉者接触到最高浓度的花粉和花蜜杀虫剂。在葫芦科作物中，减少农药投入可能会更好地平衡作物保护与授粉，降低成本并提高产量。
