Tag: plant growth regulators

The normalized relative clipping yield of annual bluegrass putting green turf in Corvallis, Ore., averaged across June, July and August treatments during 2023 and 2024, after a single application of Primo (left) or Anuew (right) combined with weekly applications of nitrogen at low N (top) or high N (bottom). Equation and R² values are from the sine wave model used to calculate relative growth suppression. The vertical line indicates the reapplication interval. (Figure: Golfdom staff)

Super Science: A recap of the research published in 2025

January 14, 2026 By Mike Kenna, Ph.D.

A summary of the research information provided by turfgrass researchers and the USGA Green Section that appeared in Golfdom this year. ...

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Photo:ioanna_alexa/ iStock / Getty Images Plus/ Getty Images

The Turf Doc: A case of ‘What’s that?’

January 8, 2026 By Karl Danneberger, Ph.D.

Two abnormalities that occur that trigger a response like “What’s that?” are annual bluegrass etiolation — or mad tiller disease — and white leaf. ...

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Photo 1. Penncross creeping bentgrass (outlined in blue) shows discoloration in response to lower nitrogen rates in evaluating 10 creeping bentgrass cultivars. (Photo by: Ohio State University)

New USGA research evaluating plant growth regulators

October 13, 2025 By Mike Kenna, Ph.D.

USGA-supported research at Ohio State and Rutgers is uncovering how plant growth regulators shape the performance of new creeping bentgrass cultivars. ...

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Photo: DSCimage/iStock / Getty Images Plus/Getty Images

Turf MD: In a growth drag race, Poa wins

April 15, 2025 By Karl Danneberger, Ph.D.

Key differences between Poa annua and creeping bentgrass on golf courses. ...

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Turf MD: Why we need to remember the benefits of PGRs

May 10, 2022 By Karl Danneberger, Ph.D.

Karl Danneberger, Ph.D., talks about the application and absorption characteristics of ingredients in plant growth regulators (PGRs). ...

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The impact of different PGR reapplication models on the turfgrass quality of a creeping bentgrass fairway mowed at 0.4 inch. (Photo by: William Kreuser, Ph.D.)

How to guide PGR applications by growing degree days

June 4, 2021 By Bill Kreuser, Ph.D.

At the University of Nebraska, our lab has been creating models to predict the duration and performance of plant growth regulators (PGRs) using growing degree day (GDD) models. We have more than 570 different models specific to grass species, the ...

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