Kansas State University


K-State Turfgrass

Category: Research

Turfgrass management by the numbers!

(By Jared Hoyle, KSU Turfgrass Research and Extension)

One of the most common question I am asked is…

“What do you think about this product?  Would you apply it?”

Well sometimes I have had experience with that product and sometimes I have not.  If not I go look for the research and look at the numbers and then respond to the question with the best information that I have. It is then up to the superintendent to apply that product or not.

You can look at the numbers as well.  You can run your own test trials and see the results with your own eyes.  In the article below titled “I used product X and my greens have never looked so good!” hits on some great points.

  • If it ain’t broke don’t fix it.
  • Ask for data to backup claims of that product.
  • Make test plots at your location. (If you have a check remember if you don’t do anything at all to that area it will not look as good as the surrounding turf.  You have to keep everything the same except what you are testing.)
  • Record numbers!
  • Did a product actually work or was it just a better year for growing turfgrass.  (Well in KS it is never easy growing turfgrass.)

Click here for the entire article – https://dcsturf.wordpress.com/2017/04/05/i-used-product-x-and-my-greens-have-never-looked-so-good/ 

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

What have you been up to? – Undergraduate Research Projects

(By Jared Hoyle, KSU Turfgrass Research and Extension)

As the temperatures start getting warmer, friends and neighbors start getting out more.  So when I run into them, the first question I get is “What have you been up to?”.  Many times people think winter is slow because the grass is not growing but actually during the winter is when we try and get a lot of things done that we don’t have time to get to in the warmer parts of the year.  But one thing that we have been up to is undergraduate research projects.

In the fall of 2016 I had three students come to my office interested in conducting an undergraduate research project.  I told them that the purposes of an undergraduate research projects are; 1. Answer a question for an issue that turfgrass managers face, 2. Learn the process to conduct research and, 3. Relate your research to more than just the turfgrass manager but have a social impact.  All three of them agreed then we started brainstorming and came up with three projects.

Undergraduate Research Project #1 – Student – Peyton South

The Effect of Human Insect Repellents on Turfgrass Growth and Recovery

Ever seen this before? https://www.extension.iastate.edu/turfgrass/blog/dr-nick-christians/mosquito-spray-can-kill-grass

That is what bug spray can do to your turf.  Peyton wanted to look into it more and see if there are differences in not only the bug sprays but if there is recovery. He is currently taking data and we will get that information out there once the project is complete.  Here are some pictures of the project.


Undergraduate Research Project #2 – Student – Dani McFadden

Will Turfgrass Colorants Blemish Clothing?

Dani’s research project was inspired by a question I got from in education event this past year. There has been lots of research on turfgrass colorants and how long they last but what will it do to the clothing of the athletes if they fall.  So Dani went out and applied a variety of different turfgrass colorants, pulled clothing across the colorants (after the recommended drying time) and then analyzed how much colorant blemish the clothing. Once her project is complete then we will be able to determine which products to recommend to athletic field managers so they can rest assure they won’t have any phone calls about stained clothing.


Undergraduate Research Project #3 – Student – Gage Knudson

Prediction of baseball on-base percentage due to infield mowing height

Sometimes there is only a spit second at first base between a baseball batter and the throw at shortstop to determine if the runner is out or safe.  One component of that split second is how fast the baseball moves through the infield.  Holding all other factors constant, Gage manipulated mowing height of a simulated baseball infield to determine the speed of a ground ball hit to the shortstop.  Then he can predict the out percentage at first base.  Gage’s interest in this project not only helps field managers with maintenance of the field but shows how important it is for the coach of baseball team to communicate with the grounds manager.  To simulate a constant speed he used a pitching machine that was aimed at the infield.  Believe it or not that one slit second can be influenced just by the mowing height of the infield.

“An ounce of prevention is worth a pound of cure.” by Benjamin Franklin – (That Goes for Preemergence Herbicides Too!)

(By Jared Hoyle, KSU Turfgrass Research and Extension)

“An ounce of prevention is worth a pound of cure” – Benjamin Franklin

When I start talking about pre-emergent herbicides this quote from Benjamin Franklin always pops in my head.  Although, Ben was giving fire-fighting advice to Philadelphians because fires were a dangerous threat at that time it does apply to many things we are dealing with right now, including spreading wild fires. (I won’t comment on that because I have no idea how to manage wild fires.) But I will talk about Pre-remergent herbicides.

Pre-emergent (PRE) herbicides prevent summer annual weed (For Example, crabgrass, goosegrass, annual sedges, and spurge) seeds from developing into mature plants.  The reason we use PRE herbicides for summer annual weed control is because these summer annuals come back every year from seeds.  So if we can stop the seed from growing then we don’t have to deal with the weeds later in the season.

For all that don’t know how a PRE herbicide works here is a very short explanation.  They do not keep the seed from germinating but kill the young germinating plant.  With few exceptions they have no effect on existing plants, so they must be applied before germination.

But like in everything in life there is an exception.  Dithiopyr can kill crabgrass as long as it is young (two- to three-leaf stage, see photo below of three leaf crabgrass) and still have some residual for continued PRE activity. It doesn’t last as long as some of the other PRE herbicides but there is flexibility if you miss your window of opportunity to apply.


So when do I put out the PRE application for summer annual weed control? Well, it depends on many things.  What summer annuals you have? Where are you located in Kansas?  Many times turfgrass managers center their PRE applications around crabgrass germination.  Crabgrass “typically” begins to germinate around May 1 or a little later in KS. April 15 is a good target date for applying a PRE because it gives active ingredients time to evenly disperse in the soil before crabgrass germination starts. The April 15 target works well for most of the state, but for southeast Kansas April 1 is more appropriate, and for northwest Kansas May 1 is best.  Additionally, weather varies from one spring to the next (As we can see this year where it is getting warmer earlier!), and with it the timing of crabgrass germination. Some turfgrass managers base their PRE application around the bloom of the Redbuds but other ways can be used as well.  Crabgrass germinates when the soil at approximately 1 cm deep reaches 55° F.  So watch your soil temperatures to see when the soil consistently reaches 55° F. Here is a great website that will give you soil temperatures for your area.


PRE herbicides do not last forever once applied to the soil. Microorganisms and natural processes begin to gradually break them down soon after they are applied. If some products are applied too early, they may have lost much of their strength by the time they are needed.  Additionally, PRE herbicides have different half-life, Koc, water solubility, and vapor pressure. This can determine how fast microbial, chemical and physical decay occurs along with infiltration, volatilization, leaching, and run-off.


Therefore, not all PRE herbicides are created equal.   Here is a list of PRE herbicides, the weeds they target and some concerns that you might want to know before applying.

Active Ingredient Weeds Controlled Concerns or Comments
benefin summer annual grasses, annual bluegrass, some-small seeded broadleaves Do not use on golf course greens.
prodiamine summer annual grasses, annual bluegrass, henbit, chickweed, spurge, some-small seeded broadleaves Only apply to well established turfgrass.
bensulide annual grasses, some broad-leaves Do not use on putting greens composed of  > 50% Poa annua.
florasulam broadleaves, dandelion, prickly lettuce, clover Packaged with Dimension 2EW, florasulam great cool temperature activity, Prevents flowering in some broadleaves (dandelions).
dithiopyr summer annual grasses, annual bluegrass, yellow-woodsorrel, some small-seeded broadleaves PRE and early post-emergence activity on crabgrass.
isoxaben broadleaves such as chickweed, henbit, spurge, plantain, others Tank-mix with a grass herbicide for broader spectrum.
pronamide annual bluegrass, perennial ryegrass, other grassy & broadleaf weeds. Do not use on cool-season turf. Restricted use pesticide.
pendimethalin summer annual grasses, annual bluegrass, yellow-woodsorrel, some small-seeded broadleaves Not recommended for turf severely thinned due to winter stress.  Split applications can be made for extended control.
metolachlor annual bluegrass, crabgrass, sedges Do not use on cool-season turf.
simazine summer annual grasses, annual bluegrass, henbit, chickweed, spurge, some-small seeded broadleaves Do not use on cool-season turf.
ethofumesate annual bluegrass, annual grasses, some annual broadleaves See label for reducing annual bluegrass in cool-season turf.
oxadiazon summer annual grasses includinggoosegrass, annual bluegrass, some-small seeded broadleaves Ronstar G and Oxadiazon 2G are only formulations labeled for use on cool-season turf.
indaziflam annual grassy and broadleaf weeds in turf Do not use on cool-season turf.
oryzalin summer annual grasses, annual bluegrass, some-small seeded broadleaves Do not use on cool-season turf except tall fescue.
dimethenamid bittercress, crabgrass, goosegrass, purslane, sedges, spurge On golf courses: Can be used on cool- and warm-season.  Other turf areas: Warm-season only.
siduron crabgrass, bermudagrass (suppression) Does not control goosegrass or annual bluegrass.

Information in this table was acquired from “Turfgrass Weed Control for Professionals” by A. Patton and D. Weisenberger, Purdue University (and 11 collaborating states including Kansas). For more information about purchasing this publication see;



***There are many combination PRE herbicides that combine these active ingredients with each other and with other POST-emergent herbicides***

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

New Weed Control Publication For Turfgrass Professionals

(By Jared Hoyle, KSU Turfgrass Research and Extension)

In 2016 Dr. Aaron Patton and Daniel Weisenberger reached out to surrounding universities to collaborate on producing a multi-state Turfgrass Weed Control for Professionals Publication.  There are 11 states, including Kansas, that worked together to help produce the 2017 edition.


Guide provides weed identification and control information that turfgrass professionals can use to develop effective weed control programs for golf courses, athletic fields, sod farms, lawns, and other turfgrass systems. Recommendations apply to most states, with input from experts in IL, IN, IA, Kansas, KY, MI, MN, MO, NE, NY, OH, and WI.

It contains images and information for identifying 105 different weed species.



Covers herbicide selection in:

  • Nonselective herbicide/fumigants for renovation
  • Nonselective herbicides for border maintenance
  • Preemergence herbicides
  • Postemergence broadleaf herbicides
  • Postemergence grass herbicides
  • Postemergence sedge herbicides
  • PGRs for general turf
  • PGRs for putting greens
  • Herbicides labeled for putting greens (PRE and POST)

The publicationl also covers many other weed control aspects like;

  • Which herbicide works best for each weed.
  • Includes notes and comments on each herbicide.
  • Control of tough weeds.
  • Provides handy comparisons of broadleaf herbicide ingredients.
  • Covers fundamentals of how herbicides work
  • frequently asked questions.


For an electronic download copy for 12.00 click here – https://mdc.itap.purdue.edu/item.asp?item_number=Turf-100-W#.WMFVKGVuD8s

For a hard copy delivered to your door (20.00) click here – https://mdc.itap.purdue.edu/item.asp?item_number=TURF-100#.WMFVDWVuD8u

Congrats to PhD student Ross Braun for national awards

Here at K-State we love working with all our students. It is particularly gratifying and exciting when they are recognized for their achievements beyond the university.

PhD student Ross Braun recently earned not just one, but two awards at the national conference of the Crop Science Society of America C5 (turfgrass) division.

He earned first prize in one of the oral presentation categories and third prize in a poster category. Way to go Ross!


# KSUTURF Teaching, Research and Extension at its BEST!

(By Jared Hoyle; KSU Turfgrass Research and Extension)

We have a lot going on out at Rocky Ford Turfgrass Research Center in Manhattan, KS.  One project is about 3 acres of new research plots with irrigation.  With the support and donations from CiteOne, Hunter, MidWest Laser Leveling, Ewing, Netfim and others (I apologize if I have left anyone out, it has been a long week) we will have new areas for future research, teaching and extension programs.  From the entire Horticulture and Natural Resources department we thank you for making this project possible!

One of the best parts of this project is being able to incorporate the Horticulture Irrigation Class.  They have been hard at work with the installation of the research plots.  From laying out the plots to digging trenches they get hands on experience with irrigation installation.

This is a great project because it is not only research plots but it is a teaching and learning experience for undergraduate students.

Enjoy the pictures and as you can see we had some issues with mother nature!  There will be more to come but just wanted to let everyone know how the Department of Horticulture and Natural Resources is combining the three missions of a land-grant university of Teaching, Research and Extension for Kansas.

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Low Water Use Turfgrass Event – Hays, KS

Tuesday evening, Sept. 20 is set for the annual Horticulture Night at the Kansas State University Agricultural Research Center in Hays. This year the emphasis is on low water use turfgrass demonstration plots, tomato and pepper varietal trials, and the Prairie Star flower performance trials.  The event is scheduled later in the summer this year than usual so attendees can better view the results of the complete season.

Dr. Jared Hoyle will be there to answer any turfgrass questions you might have!




Broadleaf Weed Control and PRE Crabgrass Control – VIDEO

(By Jared Hoyle and Jake Reeves, KSU Turfgrass Research and Extension)

Just a couple weeks ago the turfgrass team held the Annual Kansas Turfgrass Field day in Manhattan, KS at the Rocky Ford Turfgrass Research Center.  At one of the stops Dr. Jared Hoyle talked about new products that are on the marked for post-emergent broadleaf weed control and pre-emergent crabgrass control.  If you couldn’t make it out to field day here is a short little video about what you missed.

Converting Tall Fescue to Buffalograss – VIDEO

(By Jake Reeves and Jared Hoyle, KSU Turfgrass Research and Extension)

Are you thinking about converting your tall fescue lawn into buffalograss?  If you are, new research is currently being conducted at Rocky Ford Turfgrass Research Center in Manhattan, KS to pin down the best herbicide application timing to reduce the amount of time that you don’t have turf in your lawn.

Check out the video here of KSU Turfgrass Research Technician, Jake Reeves, discuss this research and how it will impact turfgrass areas across Kansas.

“Reflecting on Turfgrass” : KSU NDVI research featured in Golf Course Management

(Megan Kennelly, KSU Plant Pathology)

Research by Dr. Dale Bremer and Dr. Steve Keeley along with former students Hyeonju Lee and Kemin Su is featured in Golf Course Management. Check out the article here:


It’s an online e-magazine format and takes a minute to load.

The researchers were studying how NDVI ratings correlate to visual ratings of turfgrass quality. It’s not as simple as you might think! The article at the link above does a nice job summarizing their academic article.