Seedcorn maggot (Delia platura) is a globally distributed agricultural pest that feeds on the germinating seeds of economically important crops, including corn and beans. The larvae cause underground damage, which can lead to stand loss. For decades, D. platura has been managed using insecticide-coated seeds, but following the ban on neonicotinoid-coated corn, soy, and wheat seeds in New York State, this practice will no longer be available. Degree day models have been used to predict the emergence of the overwintering generation of agricultural pests since the late 1900s. However, the terminology used in the literature to distinguish degree day thresholds for first emergence and peak emergence is unclear, and previous reports of a 360 degree day emergence threshold did not align with field observations. In 2023, we captured the first emergence at four sites, and in 2024, we monitored adult D. platura at 25 sites in New York State. We observed the first adult emergence between 52 and 197 accumulated degree days (98 ± 7 degree days, mean ± 1 SE) using a biofix of January 1st, confirming that in New York State, D. platura emergence is earlier than previously reported values. Additionally, we note adult activity during December 2023 and January 2024, suggesting that warming winters may impact our ability to predict pest emergence. We propose future models should incorporate both degree day information and other regionally specific factors known to impact pests, including farm management, soil conditions, and landscape composition, for more accurate predictions.

中文翻译：

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纽约州首次出现的 Delia platura 的度日门槛验证


种子玉米蛆 （Delia platura） 是一种分布于全球的农业害虫，以玉米和豆类等经济重要作物的发芽种子为食。幼虫会造成地下破坏，从而导致林分损失。几十年来，D. platura 一直使用杀虫剂包衣的种子进行管理，但在纽约州禁止使用新烟碱类化合物包衣的玉米、大豆和小麦种子后，这种做法将不再可用。自 1900 年代后期以来，度日模型一直被用于预测农业害虫越冬一代的出现。然而，文献中用于区分首次出现和峰值出现的度日阈值的术语尚不清楚，以前关于 360 度日出现阈值的报告与现场观察不一致。2023 年，我们在 4 个地点捕获了首次出现，2024 年，我们在纽约州的 25 个地点监测了成年 D. platura。我们使用 1 月 1 日的生物固定观察到 52 到 197 个累积度日（98 ± 7 度天，平均 ± 1 SE）之间的第一次成虫出现，证实在纽约州，D. platura 出现的时间早于以前报告的值。此外，我们注意到 2023 年 12 月和 2024 年 1 月期间的成虫活动，这表明冬季变暖可能会影响我们预测害虫出现的能力。我们建议未来的模型应结合度日信息和已知影响害虫的其他区域特定因素，包括农场管理、土壤条件和景观成分，以实现更准确的预测。