DiscoverTurfgrass EpistemologyS3 E55 Dew, Nitrogen, and Dollar Spot
S3 E55 Dew, Nitrogen, and Dollar Spot

S3 E55 Dew, Nitrogen, and Dollar Spot

Update: 2025-10-29
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Can something as simple as mowing time really stop a turfgrass disease? In this episode of Turfgrass Epistemology, we look back at a landmark 1996 study by Williams, Powell, Vincelli, and Dougherty from the University of Kentucky — a paper that changed how superintendents think about dew, nitrogen, and dollar spot control.


Dollar spot (Sclerotinia homoeocarpa) thrives on leaf moisture. Williams et al. tested what happens when you simply remove that moisture early in the morning. Their data were stunning — mowing or “poling” to knock dew off reduced dollar spot by as much as 81% on fairways and 53% on greens. That’s before any fungicide was even applied. Add moderate nitrogen fertilization, and disease pressure dropped even further. Clipping removal, on the other hand, didn’t matter much.


This episode explores what these results mean for modern turf management. How does dew act as a bridge for fungal infection? Why does nitrogen strengthen bentgrass against disease? And what does this tell us about integrating simple cultural practices with fungicide programs? Join Dr. Travis Shaddox as we revisit this foundational study — proof that sometimes, the mower is mightier than the fungicide.


📘 Source: Williams, D.W., A.J. Powell Jr., P. Vincelli, and C.T. Dougherty. 1996. Dollar Spot on Bentgrass Influenced by Displacement of Leaf Surface Moisture, Nitrogen, and Clipping Removal. Crop Science 36:13 04–1309.


🔬 Keywords: Dollar Spot, Bentgrass, Dew Removal, Nitrogen, Turfgrass Disease, Integrated Management

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S3 E55 Dew, Nitrogen, and Dollar Spot

S3 E55 Dew, Nitrogen, and Dollar Spot

Travis Shaddox