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October 22, 2014

Isaac Mertz is a MS student at Iowa State specializing in turfgrass science.  An update on his research appeared in Golf Course Management this month under the heading "Cutting Edge Research".  The abstract from his study that he will present at the American Society of Agronomy meetings in Long Beach, Ca. in a couple of weeks appears below.  Congratulations Isaac.

The full text of the GCM article is at


Tryptophan is one of the 22 essential amino acid and acts as a building block in protein synthesis, as well as a biochemical precursor for serotonin, niacin, and auxin in most organisms. Previous research has shown that applying biosolids boosted with auxin coming from tryptophan may enhance plant defense chemical responses during limited soil moisture conditions.  This occurs through increases in root production as well as endogenous hormone levels that can result in plant growth regulating activity. Tryptophan is produced industrially, which results in a significant amount of byproducts. Tryptophan byproduct (TRP-B) is currently considered a waste product, however, its amino acid and nutrient contents make it an intriguing subject for the use as a growth promoter for turfgrasses. The objective of this research was to determine whether applications of TRP-B improve ‘Penn-A4’ creeping bentgrass (Agrostis stolonifera L.) performance more than applications of pure tryptophan and/or urea. Creeping bentgrass plugs taken from sand-based putting greens at both the Virginia Tech Turfgrass Research Center (Blacksburg, VA) and the Iowa State Horticulture Research Station (Ames, IA) were transplanted into pots and allowed to reestablish in a growth chamber at both respective universities before being treated.  Treatments included TRP-B, urea, and pure tryptophan + urea, and were applied every 14 days at three different rates. Application rates were based on the amount of nitrogen being applied and were 2.5, 12.2, and 24.5 kg N ha-1.  At trial end (42 days), plant parts were harvested and used for analysis. At 24.5 kg N ha-1, TRP-B and pure tryptophan + urea increased root mass by 18.2% and 16.3% respectively compared to urea only. Creeping bentgrass treated with TRP-B can result in increased root production, but the response is rate dependent.



August 21, 2014

At the annual turfgrass fieldday, Laura filmed an instructional video on how to sample for possible nematode problems.  That film is now finished and it has been put up on line at the following location:

Give Laura a call if you have any more questions about how to submit samples to the Plant and Insect Diagnostic lab.

Ryan has established treatments on an experimental green at the research station to evaluate a number of nematicides with and without Heritage (Azoxystrobin) fungicide.  Ryan will be posting information on the blog as information becomes available.

Laura at this years fieldday.

Laura  Jesse

Plant & Insect Diagnostic Clinic

Iowa State University Extension

327 Bessey Hall

Ames, IA  50011



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Iowa State Turf Club Teams Compete

February 14, 2019

Iowa State University Turf Club students have been busy competing in various turf competitions. At the National Sports Turf Managers Association (STMA) Annual Meeting and Tradeshow in Phoenix the Iowa State team of Kylah Crooks, Thomas Gould, Alex Polnow, and Marcus O'Brien took first place in the Student Challenge 4-year division. This was the second year in a row for Iowa State to win the 4-year division. There were 31 teams in the competition. 

Iowa State Turf Bowl 4-year Winning Team
Pictured above (left to right) are members of the 4-year winning team: Sarah Martin (STMA President), Thomas Gould, Kylah Crooks, Marcus O'Brien, and Alex Polnow.

Two weeks later at the Golf Course Superintendents Association of America (GCSAA) Conference, Iowa State Turf Club finished 2nd place out of 63 teams in the GCSAA Turf Bowl. This conference was in San Diego, CA. The students also won the Collegiate Spirit Award, for answering a series of Tweets in the weeks before the conference.


Iowa State 2nd place team
Pictured above are members of the second place GCSAA Turf Bowl Team: (left to right) Alex Polnow, Jarrett Chapman, Thomas Gould, and Aaron Butler.


Iowa State students with the Collegiate Spirit Award
Pictured above are Iowa State Turf Club members with the Collegiate School Spirit Award at the GCSAA Turf Bowl.


These turf competitions consist of proper turfgrass identification, insect, disease and weed identification, turf management scenarios, soil problems, and mathematic problems related to turfgrass management. In addition to identification and short answer, the students must be able to identify equipment, assemble irrigation and complete an essay.

Well done Cyclones!



October 21, 2020

Gray Snow Mold is a common winter disease of creeping bentgrass on golf course greens in central Iowa.  It is caused by the fungi Typhula incarnata (and a few other species) It occurs during the winter, usually under snow cover.  We generally see the cottony mycelia of the organism as the snow melts in the spring. 


This disease has a resting stage called “sclerotia” (see picture below).  These are quite large and can be seen with the naked eye.  Under just the right conditions, the sclerotia will germinate, which results in rather large white to brown fruiting bodies.  These can be one half inch or more.  The germinating sclerortia pictured below are standing erect, but they can also result in a “fiddle head” like appearance as they emerge.  It is very rare to see the germinating sclerotia.  The conditions that bring this about is an early snow fall on actively growing turf, such as we just had in central Iowa.  Watch your greens for this phenomenon and send me some pictures if it shows up.  I have only seen it twice in 41 years.  They will go away very quickly. 


These are the sclerotia as they appear on creeping bentgrass.

This is what the germinatiing sclerotia look like just after an early snow melts.


The pictures are from the American Society of Agronomy turfgrass disease slide set.


Adam W Thoms

Picture of Adam Thoms
Assistant Professor
Area of Expertise: 
turfgrass education, sports turf management