The USGA Turfgrass and Environmental Research
program has funded projects at land-grant universities across the country at a
cost of over $40 million since 1920. Three recently funded projects at Clemson
and North Carolina State University have been done over the past few years. This
web update is the first in a three-part series on how these USGA-funded
research projects benefit golfers.
Title: Investigations into the Cause and Management of Etiolation on Creeping
Bentgrass Putting Greens
North Carolina State University
David Ritchie and Joseph Roberts
bentgrass remains a popular putting turf used throughout most of the Southeast.
An increasing problem in recent years has been yellowing and elongation of
bentgrass grass tillers (stems and leaves). This has been termed etiolation. In
some cases, these outbreaks cause gradual turf thinning and death of bentgrass
during the summer months. Scientists and superintendents have speculated as the
reason for this problem, including bacteria, fungi, viruses or nutritional
The focus of this research was to determine the
cause and develop management programs for this bentgrass putting green issue.
Research done previously at Michigan State University isolated the bacteria Acidovorax avenae from etiolated
bentgrass from a North Carolina golf course. North Carolina State University researchers
have since identified 16 genera of bacteria, including Acidovorax avenae, from bentgrass turf exhibiting etiolation and
general summer decline symptoms. Research has shown that additional bacteria,
including but not limited to Xanthomonas
translucens, may be capable of infecting creeping bentgrass turf resulting
in etiolation and decline during stressful summer periods.
A field study was initiated during 2011 to determine
if the use of biostimulants and plant growth regulators contributes to
bentgrass etiolation. These products are commonly used on bentgrass putting
greens during the summer months. Throughout multiple years of study,
biostimulants did not have a significant effect on etiolation development. Astron
biostimulant typically had the most etiolation but was often statistically
similar to the non-treated control. Plant growth regulators have significantly
impacted etiolation development but in different ways depending on the
bacterium present causing etiolation. Primo MAXX® reduced etiolation caused by X. translucens in fall 2011. In 2012,
the same plots were inoculated with Acidovorax
avenae. During this season, Primo MAXX growth regulator enhanced etiolation
compared to untreated plots, regardless of biostimulant treatment.
Surprisingly, turf decline was not observed in any year of the experiment and
Primo MAXX often improved turf quality even when etiolation was observed. Additional
research is currently being conducted to evaluate additional growth regulators
for their influence on etiolation.
Future research will focus on whether bacteria cause
etiolation through direct production of plant hormones or by modifying the
plant host to cause turf decline. More studies are needed about the use of
Primo MAXX during the summer months on bentgrass putting greens and its impact
on turf quality while reducing etiolation.
Golfers Should Know
Golfers should know that multiple species of
bacteria can cause this decline on bentgrass putting greens. Although limited
management options exist to help with this summer decline problem of bentgrass
putting greens, USGA-sponsored research is underway to find a solution.
For additional information on this USGA research
project, please see Investigations
into the Cause and Management of Etiolation on Creeping Bentgrass Putting
Source: Patrick O'Brien (email@example.com) and Chris Hartwiger (firstname.lastname@example.org)
Information on the
USGA’s Course Consulting Service