Microdochium patch is a turfgrass disease caused by the fungal pathogen Microdochium nivale (Fr.) Samuels and I.C. Hallett that occurs in cool, humid conditions, which are commonplace in the U.S. Pacific Northwest and northern Europe. Pesticide restrictions in certain areas make suppressing Microdochium patch challenging, and alternative control methods are desired. Previous research has shown that mineral oil, S, and phosphorous acid (H₃PO₃) suppress Microdochium patch, but abiotic damage was associated with repeated mineral oil applications. Two field experiments in western Oregon focusing on the suppression of Microdochium patch and turfgrass quality on annual bluegrass (Poa annua L.) greens are presented. The first experiment compared tank mixtures of mineral oil and S or mineral oil and H₃PO₃ in rotation with a tank mixture of S and H₃PO₃. The second experiment focused on seasonal rotations that excluded mineral oil in certain months and compared 2- and 3-wk application frequencies. All rotations, in both experiments, suppressed Microdochium patch compared to the non-treated control, although differences in turfgrass quality were observed. In the first experiment, green cover percentage was used to assess abiotic damage. A mineral oil and H₃PO₃ tank mixture rotated every 2 wk with S and H₃PO₃ resulted in the highest green cover percentage. In the second experiment, most of the applications made every 2 wk completely suppressed Microdochium patch. Two treatments applied every 2 wk that withheld mineral oil in the winter months resulted in turfgrass quality ratings considered acceptable for putting greens on all rating dates.

中文翻译：

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使用矿物油、硫磺和亚磷酸的轮换抑制 Microdochium 斑块

Microdochium patch 是一种草坪病，由真菌病原体Microdochium nivale (Fr.) Samuels 和 IC Hallett 引起，发生在凉爽潮湿的条件下，这在美国太平洋西北部和北欧很常见。某些地区的农药限制使得抑制 Microdochium 斑块具有挑战性，并且需要替代控制方法。先前的研究表明，矿物油、S 和亚磷酸 (H ₃ PO ₃ ) 会抑制 Microdochium 斑块，但非生物损害与重复使用矿物油有关。在俄勒冈州西部进行的两项田间试验，重点是抑制一年生早熟禾（Poa annua）上的 Microdochium 斑块和草坪草质量L.) 呈现绿色。第一个实验将矿物油和 S 或矿物油和 H ₃ PO ₃的罐式混合物旋转与 S 和 H ₃ PO ₃的罐式混合物进行比较。第二个实验侧重于季节性轮换，在某些月份排除矿物油，并比较 2 周和 3 周的施用频率。在两个实验中，与未处理的对照相比，所有旋转都抑制了 Microdochium 斑块，尽管观察到草坪质量的差异。在第一个实验中，绿色覆盖百分比用于评估非生物损害。矿物油和 H ₃ PO ₃罐混合物每 2 周与 S 和 H ₃ PO ₃轮换一次导致最高的绿色覆盖率。在第二个实验中，大多数应用程序每 2 周完全抑制 Microdochium 补丁。每 2 周进行两次处理，在冬季不使用矿物油，结果草坪质量评级被认为可以在所有评级日期用于推杆果岭。