Abstract Fungicides may be applied to corn using an airplane or a ground sprayer. Questions regarding which technology is better at coverage throughout the corn canopy are common among farmers and agronomists. The objectives of this study were to compare the efficacy of three application technologies in terms of canopy coverage, foliar disease management, lodging and yield response. A fungicide was applied to corn at silking (R1) by airplane, a traditional ground sprayer with an overhead spray boom, or a ground sprayer with 360 Undercover sprayers that hang down into the canopy. Replicated on-farm and small-plot trials were conducted across Iowa in 2017 and 2018 for a total of nine site-years. Fungicide coverage was measured as ppm of pyrenetetrasulfonic acid (PTSA) dye detected on corn leaves, percent coverage of water sensitive spray cards, and percent of total application received. Foliar disease data were collected in three zones of the canopy: the upper canopy (UC), the ear leaf (EL), and the lower canopy (LC). Coverage and disease severity were not correlated with yield. In the 2017 on-farm trials, all three application methods delivered similar fungicide coverage on the EL and LC. In 2018, traditional and undercover methods provided greater coverage when compared to aerial application, however, fungicide distribution within the canopy was similar among the application methods. Overall trends indicated the traditional spray method delivered the best coverage to the UC. The aerial spray method delivered the least coverage to the EL and LC for three site-years. The undercover spray method resulted in greater coverage to the LC. Foliar fungicides applied by all three application methods significantly reduced foliar disease severity, and fungicide application methods did not differ from each other, and reduced disease severity to similar levels. Lodging was reduced approximately 50–75% by all application methods. For 8 of 9 site years, fungicide application did not affect yield significantly (P > 0.05), although numerically less yield was consistently recorded in the non-sprayed controls. Our findings indicate these three application technologies were similarly effective in reducing plant disease levels and lodging. But the reduction in disease due to fungicide application did not affect corn yield.

中文翻译：

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玉米冠层覆盖、病害严重程度、倒伏和产量的空中和地面喷洒杀菌剂应用技术比较

摘要 杀菌剂可以使用飞机或地面喷雾器喷洒到玉米上。关于哪种技术覆盖整个玉米冠层的问题在农民和农艺师中很常见。本研究的目的是比较三种应用技术在冠层覆盖、叶面病害管理、倒伏和产量响应方面的功效。用飞机、带有高架喷杆的传统地面喷雾器或带有悬挂在树冠中的 360 Undercover 喷雾器的地面喷雾器在脱丝时 (R1) 将杀菌剂喷洒到玉米上。2017 年和 2018 年在爱荷华州进行了重复的农场和小块试验，总共九个地点年。杀菌剂覆盖率测量为在玉米叶上检测到的芘四磺酸 (PTSA) 染料的 ppm、水敏喷雾卡的覆盖率百分比、和收到的申请总数的百分比。在冠层的三个区域收集叶病数据：上部冠层 (UC)、穗叶 (EL) 和下部冠层 (LC)。覆盖率和疾病严重程度与产量无关。在 2017 年的农场试验中，所有三种施用方法都为 EL 和 LC 提供了相似的杀菌剂覆盖率。2018 年，与空中施用相比，传统和卧底方法提供了更大的覆盖范围，但是，不同施用方法之间的树冠内杀菌剂分布相似。总体趋势表明，传统的喷雾方法为 UC 提供了最佳的覆盖范围。在三个站点年中，空中喷洒方法对 EL 和 LC 的覆盖范围最小。卧底喷雾方法导致对 LC 的覆盖更大。所有三种施用方法施用的叶面杀菌剂均显着降低了叶面病害的严重程度，并且杀菌剂施用方法彼此没有区别，并且将病害严重程度降低到相似的水平。通过所有应用方法，住宿减少了大约 50-75%。在 9 个场地年份中的 8 个年份中，尽管未喷洒对照中的产量在数值上始终较低，但杀菌剂的施用并未显着影响产量（P > 0.05）。我们的研究结果表明，这三种应用技术在减少植物病害水平和倒伏方面同样有效。但由于施用杀菌剂而减少病害并没有影响玉米产量。通过所有应用方法，住宿减少了大约 50-75%。在 9 个场地年份中的 8 个年份中，尽管未喷洒对照中的产量在数值上始终较低，但杀菌剂的施用并未显着影响产量（P > 0.05）。我们的研究结果表明，这三种应用技术在减少植物病害水平和倒伏方面同样有效。但由于施用杀菌剂而减少病害并没有影响玉米产量。通过所有应用方法，住宿减少了大约 50-75%。在 9 个场地年份中的 8 个年份中，尽管未喷洒对照中的产量在数值上始终较低，但杀菌剂的施用并未显着影响产量（P > 0.05）。我们的研究结果表明，这三种应用技术在减少植物病害水平和倒伏方面同样有效。但由于施用杀菌剂而减少病害并没有影响玉米产量。