In this episode of Turfgrass Epistemology, we take a close look at one of the most frequently cited studies in turfgrass pathology — Golembiewski and Danneberger’s 1998 Agronomy Journal paper exploring how trinexapac-ethyl (TE) and nitrogen fertility influence the severity of dollar spot (Sclerotinia homoeocarpa) in creeping bentgrass.

The researchers found that TE, a popular plant growth regulator, didn’t increase disease as many feared — in fact, it reduced dollar spot when combined with adequate nitrogen. This discovery challenged the prevailing assumptions of the time and suggested that growth regulation and fertility could work together to reduce fungicide reliance on golf course fairways.

In this discussion, we unpack:

The experimental design and methodology behind the study.

Why mowing height and growth regulation changed disease outcomes.

How nitrogen rate influenced both dollar spot suppression and thatch accumulation.

What this means for modern integrated pest management (IPM) strategies in turfgrass systems.

By the end, we’ll consider whether the mechanisms observed in 1998 still hold true today — and what this research can teach us about evidence-based turf management in the age of marketing claims and quick fixes.

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Paper discussed:

Golembiewski, R. C., & Danneberger, T. K. (1998). Dollar spot severity as influenced by trinexapac-ethyl, creeping bentgrass cultivar, and nitrogen fertility. Agronomy Journal, 90(4), 466–470. https://doi.org/10.2134/agronj1998.00021962009000040004x

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

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