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K-State Turfgrass

Category: Research

Zoysiagrass Seedhead Suppression

By Dr. Jack Fry

Below-average spring temperatures and a lot of cloud cover haven’t been beneficial for growth of warm-season grasses. Nevertheless, days are getting longer, and Meyer zoysia began to produce seedheads in northeast Kansas last week. Significant work was done at K-State on zoysia seedhead suppression by Dr. Jared Hoyle, along with Dr. Aaron Patton at Purdue University. Seedheads on Meyer have a purple tone to them, but after mowing, the seed stalks leave an undesirable white cast on golf course fairways and tees. The plant growth regulator ethephon (trade name Proxy) is effective at suppressing zoysia seedheads if it is applied at the proper time the previous autumn. Manoj Chhetri, a current Ph.D. student, is working on better refining application time for Proxy to suppress zoysia seedheads. The Golf Course Superintendents Association of America, along with the Heart of America Golf Course Superintendents Association and Kansas Turfgrass Foundation, are sponsoring this zoysia seedhead suppression research that is summarized in Golf Course Management magazine (link below).

https://www.gcmonline.com/course/environment/news/zoysiagrass-seedheads

Seedheads are just beginning to emerge on Meyer zoysiagrass in Olathe, KS. Best suppression of the seedheads occurs when the growth regulator Proxy is applied in autumn.

Progress in Bermudagrass Breeding

By Dr. Jack Fry

This is the time of year when we hope all warm-season grasses green up uniformly with no signs of winter injury.  K-State researchers have been working with Dr. Yanqi Wu, bermudagrass breeder at Oklahoma State University (OSU), for the past several years.  Dr. Wu is consistently working to improve bermuda cold hardiness and release improved cultivars for the transition zone region of the U.S.  ‘Latitude 36’ and ‘Northbridge’, a couple of high quality, vegetatively propagated bermudas, were released by OSU in 2010.  These have been used extensively on sports fields and golf courses.  However, there have been some winters in which significant winter injury occurred to these cultivars in Kansas.  In the article linked below, you’ll see that some of the new bermudas that are being evaluated by OSU and K-State have superior freezing tolerance to any of the existing cultivars in use.  This likely means that in the next several years, we’ll have improved bermudas for our region that will be more likely to tolerate extremely cold winters.
Article here:

https://newprairiepress.org/cgi/viewcontent.cgi?article=7770&context=kaesr

Flowering Ornamentals and Crabgrass Emergence

By Jack Fry and Ward Upham

Efficacy of some preemergence herbicides is strongly dependent upon the timing of application relative to crabgrass emergence.  For example, application of a preemergence herbicide that has a relatively short residual, such as pendimethalin, closer to crabgrass emergence, will extend the period of time which the herbicide is effective.  Herbicides with longer residuals, such as prodiamine (Barricade), are often applied well before crabgrass emergence, and can even be effective if applied late in the previous autumn.

In our climate, calendar dates don’t always adequately identify crabgrass emergence or herbicide application.  Biological indicators, such as flowering ornamentals, may be useful for predicting crabgrass emergence and preemergence herbicide application.

From 1995 to 1997, K-State researchers worked with those at the Univ. of Nebraska to identify ornamentals at each location which best represented crabgrass emergence and preemergence herbicide application time.  Ornamentals evaluated were bridal wreath spirea, callery pear, daffodil, flowering quince, forsythia, iris, lilac, redbud, saucer magnolia, tulip, and vanhoutte spirea.  Obviously, there may be ornamental cultivar differences in blooms, so this was an average of those observed.  In addition, crabgrass can vary in rate of emergence, but getting an herbicide out before the first plants emerge is preferable.  For this article, we’ll focus on results in Kansas.

Crabgrass emergence in bare soil and thin turf was evaluated at the Rocky Ford Research Center in Manhattan. Over three years, the earliest date of crabgrass emergence in bare soil was April 15 1995, whereas the latest date was May 9, 1996.  In the thin turf (10% bare soil evident while standing), the earliest date of emergence was May 5, 1997 and the latest date was May 22, 1995.

Withering of blooms was a better indicator of crabgrass emergence, particularly in thin turf.  In this case, we looked at bloom wither and then compared it to a date 2 weeks prior to emergence.  This 2-week window would allow time for the herbicide to be applied. In Kansas, withering of most ornamentals was not useful for estimating emergence of crabgrass in bare soil, as emergence often occurred before blooms had withered. However, a date 2 weeks prior to  crabgrass emergence in bare soil could be estimated by adding 6 to 12 days to the date of daffodil wither.

Bloom wither of flower ornamentals was used as a date to determine time of application of short-residual preemergence herbicides (a date 2 weeks prior to crabgrass emergence)

 

Flower wither of all ornamentals could be used indicators of emergence (and herbicide application date) in thin turf in Kansas (see Table 1 below). For example, by adding 28 to 33 days to the date of forsythia bloom wither, you will estimate a date 2 weeks prior to crabgrass emergence in thin turf, which would allow time for preemergence herbicide application.  This timeline is quite different from the often used theory that herbicides must be put down at the time forsythia blooms.  Ultimately, biological indicators, along with soil temperatures, will be better indicators of for crabgrass emergence and application of short-residual preemergence herbicides than calendar dates.

Table 1.  Ornamentals and the number of days to be added to flower wither to estimate the date 2 weeks prior to crabgrass emergence in thin turf.  Data were based upon observation of ornamental blooms and crabgrass emergence for a 3-year period.

Ornamental Number of days to add to bloom wither to estimate the date 2 weeks before crabgrass emergence (range allows for standard error)
Bridal wreath spirea 4 to 13
Callery pear 32 to 41
Flowering quince 36 to 42
Forsythia 28 to 33
Iris 8 to 15
Lilac 17 to 22
Redbud 25 to 32
Saucer magnolia 28 to 32
Tulip 21 to 29

 

Note – This article is based upon:

Fry, J., S. Rodie, R. Gaussoin, S. Wiest, W. Upham, and A. Zuk.  2001.  Using flowering ornamentals to guide preemergence herbicide application in the Midwest U.S.  International Turfgrass Society Research Journal.  p. 1009-1012.

Student Spotlight: Dani McFadden

By Brooke Garcia

Meet Dani McFadden! 

Dani McFadden is currently enrolled at Kansas State University pursuing her M.S. in Turfgrass Science, with an emphasis in Weed Science. She anticipates graduating in May 2021.

McFadden also holds an undergraduate degree from K-State in Horticulture, with a focus in Golf Course and Sports Turf Management.

When outside of class, McFadden loves walking around golf courses, sports fields, and home lawns to apply what she is learning in school. She enjoys being able to identify weeds and common diseases, as well as applying her knowledge of herbicides and fungicides.

McFadden’s favorite hobbies include playing golf with friends, fishing, and attending sporting events. More specifically, she likes attending sporting events that are played on natural grass.

Research Focus: Testing Labeled Restrictions on Seeding Timings after Herbicide Application

Here is what McFadden has to say about her research…

“Many people want to know when they can seed their lawn after herbicide application. Most labels restrict seeding until 2-4 weeks after application. My research includes seeding a stand 0, 3, 7, and 14 days after herbicide application along with the effects of different irrigation amounts on seedling germination. I am also doing research on tall fescue conversion to buffalograss after glyphosate applications.”

What’s next for Dani McFadden?

McFadden will always love mowing greens in the early morning while watching the sunrise. This is something she hopes everyone will have the chance to do. Looking ahead, she hopes to start a career with a chemical company as a territory manager. Through networking, she can continue to connect with great superintendents and turf managers in this industry. The “people in this industry is what makes being a turfgrass student so great,” says McFadden. 

Student Spotlight: Nic Mitchell

By Brooke Garcia

Meet Nic Mitchell! 

Mitchell is currently enrolled at Kansas State University pursing his Master’s degree in Horticulture, with an emphasis in Turfgrass Science and Weed Science. His undergraduate degree is from University of Nebraska-Lincoln in Turfgrass and Landscape Management.

So we asked him….why Turfgrass? 

Mitchell highlighted his love for turfgrass began around the time when his parents let him mow the lawn. He grew up on a nine-hole golf course in Aurora, Nebraska, and he became interested in the various mowers and different heights of cut.

Mitchell also shared his passion for playing golf. He had the opportunity to work several summers at his hometown golf course, where his interest in turfgrass continued to grow. Throughout his college studies, he eventually changed majors to pursue Turfgrass Management. This opened the doors to a variety of unique learning opportunities, including an internship in Jackson, Wyoming and a marketing internship with WinField United. These experiences helped Mitchell realize that he wanted to work in the turfgrass industry.

Dr. Jared Hoyle presented Mitchell with the opportunity to attend Kansas State University to work towards his M.S. Mitchell says that he has had a wonderful experience, and he is forever grateful for the opportunity to be apart of the K-State family.

Let’t talk research. 

Mitchell’s research is focused around Herbicide Programs for Seasonal Windmillgrass Control. Here is what Mitchell has to say about his research:

Windmillgrass (Chloris verticillata Nutt.) is a problematic perennial grassy weed commonly found in the mid-west. Currently, there are the only two labeled chemical control options in turfgrass. Tenacity (mesotrione) is labeled for two applications for control while Pylex (topramezone) is labeled for a single application for control. We conducted research to determine if a single application of a common selective perennial grass herbicides would completely control windmillgrass, and to their efficacy when applied at spring, summer, and fall application timings. The next research study that we conducted was to explore the addition of triclopyr to mesotrione, topramezone, and fenoxaprop as well as triclopyr alone. Sequential applications of these herbicides and herbicide combinations were also applied. The last research trial we conducted was to determine the effects of windmillgrass response to glyphosate at different rates with fall applications similar to common recommended perennial weed control options.”

What’s next for Nic Mitchell?

Mitchell will be finishing up his M.S. program this December. His thesis presentation is on December 2nd, 2019 at 12:00pm in Throckmorton Plant Sciences Center. Following his thesis, he will be working for Corteva Agriscience as an Associate Territory Manager with their Turf and Ornamental business. Wish him the best of luck on his future endeavors!

See below for more information on his thesis presentation:

Large Patch Evaluation Study Update

By: Manoj Chhetri

With temperatures cooling down and days being shorter, we are already starting to see warm-season grasses, including zoysiagrass, going to sleep. At the Rocky Ford Turfgrass Research Center, located in Manhattan, KS, we have shut down the irrigation in warm-season plots.

Our zoysiagrass in the large-patch tolerant breeding plot is not cooperating with us as much as we wanted. We inoculated the field in mid-September with fresh Rhizoctonia pathogen and kept the field pretty wet to encourage fungi to flourish. However, to our dismay, we did not see much of the disease activity, except in a few poor drainage spots. With disease research, it is the type of research where we want disease pathogens to have no mercy on us. We are impatiently waiting for spring, which in fact is a more favorable time of the year for large patch activity.

We are hopeful that we have at least one or two new zoysiagrass progeny that possess greater large patch tolerance. Again, it is hard to make comparison and evaluate when we don’t have disease pressure. So far, we have narrowed down to 10 best progeny out of 60. On the positive note, we have seen more disease pressure on our non-selected progeny than in our top-ten selected progeny. This tells us that we did a good job on choosing those ten-best progeny.

This project is aiming to develop a large patch tolerant zoysiagrass that can significantly reduce cost on fungicides and protect the environment. It is a collaborative project between Texas A & M and K-State University.

Pictured Above: Zoysiagrass progeny evaluated in large patch disease environment.

Pictured Above: One of the zoysiagrass progeny showing large patch in one inoculated half (right side) and fungicide treated cleaner side on other half (left side).

Research in progress: zoysia seedhead suppression

(Megan Kennelly, KSU Plant Pathology)

I was out looking at our zoysiagrass breeding plots the other day and in a couple of plots I saw some seedhead development:

 

This was unusual, as we typically see this in spring, and it’s probably just a unique physiology of these couple of breeding lines. Anyway, this observation prompted me to mention that we are continuing KSU’s work on zoysiagrass seedhead suppression. You may have seen the articles about the prior excellent work by Dr. Hoyle and colleagues which you can view here:

Suppressing Meyer zoysiagrass seedheads

and here (academic peer-reviewed version)

https://dl.sciencesocieties.org/publications/cftm/abstracts/4/1/180012?access=0&view=pdf

We are following up on this work with additional trials to hone in on the biology and management of seedheads, fine-tuning application timings of ethephon. Stay tuned for results in the coming 1-2 years as we collect data. The project team members are PhD student Manoj Chhetri, Jack Fry, Jared Hoyle, me, and Aaron Patton (Purdue). The project is funded by the GCSAA, Heart of America Golf Course Superintendents Association, and Kansas Turfgrass Foundation.

Recent Release: Free Soil Moisture Mapping Protocol

Dr. Chase Straw, Turfgrass Scientist at the University of Minnesota, informed us of the recent release of a free soil moisture mapping protocol that can be utilized by golf course superintendents to assist them with fairway irrigation decisions. The protocol explains how to collect GPS soil moisture data with a commercially available device (FieldScout TDR 350), which are then used to generate fairway soil moisture maps with free software. The maps could be used as a tool to program an irrigation system to irrigate based on the soil moisture variability across a golf course, among possibly many other things.

More information about the protocol, in addition to details regarding how the Minnesota Golf Course Superintendents Association of America chapter is utilizing it as a service to their members, can be read from a recent blog post on the UMN turfgrass website.

The protocol can be downloaded here.

The protocol requires a $0 licensing agreement. FREE!!! Should you have any questions, don’t hesitate to reach out to Dr. Chase Straw (cstraw@umn.edu) and his team at the University of Minnesota.

 

Zoysia breeding line evaluation work continues

(Megan Kennelly, KSU Plant Pathology)

KSU continues its work with the turf breeding team at Texas A&M and colleagues at Purdue. We recently inoculated some breeding lines with the large patch pathogen. We grow the fungus on sterilized oats then bury it just under the thatch layer. Sometimes we see symptoms in fall, but often we do not see them until spring. Scientific research takes a lot of patience :). In the meantime, we are keeping the plots moist to foster fungal growth.

In the meantime, large patch is active especially in wet areas:

Take note of these areas. It’s too late to fertilize zoysia now, but when spring comes around a bump of slow-release N may prompt recovery. In the meantime there may be actions you can take to improve drainage.

The rain didn’t stop us….Turfgrass Field Day 2019!

A huge thank you to everyone who attended the 2019 Turfgrass Field Day in Olathe, KS. Our morning was filled with rain, but most attendees waited it out to learn more about the Turfgrass research + insect/disease updates from K-State   specialists. The BBQ lunch was a big incentive for waiting it out too… 🙂

We wanted to share a few pictures from the event. There were 8 different stops at the field day. Here are the highlights:

  • Tree Pruning: Principles and Practices— Tim McDonnell taught about the different types, methods and reasons for tree pruning. Specifically, he demonstrated structural, raising and thinning practices, as well as making proper pruning cuts.

  • Ornamental Potpourri — Cheryl Boyer gave updates for ornamentals in Kansas, including the status of the John C. Pair Horticulture Research Center, popular new cultivars from local growers, an Earth-Kind Ninebark trial, and new Facebook marketing research results. She had a beautiful booth, full of luscious plants from KAT Wholesale Nurseries and Loma Vista Nursery.

  • New Tall Fescue Cultivars — Steve Keeley shared insights on a new tall fescue cultivar trial with over 130 entries that were established at Olathe in 2018. He showed the top performers and gave recommedations for tall fescue cultivars in Midwest lawns and sports turf.

  • Turf & Ornamental Insect Update —Raymond Cloyd shared an update on insect and mite pests of ornamentals and turfgrass, including new insecticides and miticidies, common insect and mite pests of 2019, and lots of “bug” samples.

  • Turf and Ornamental Disease Update—Megan Kennelly talked about diseases and stresses and how to identify and manage them. She also showed some tall fescue/zoysia blend plots and demonstrataed how the two species can complement each other.
  • Managing Shaded Turf —Dale Bremer talked about shade stress and how it affects turf performance, along with options to maintain turf quality in shade.

  • Turfgrass Weed Control Update — Jared Hoyle & Dani McFadden covered many aspects of turfrgass weed control advancements, including information about new herbicides, and how they influence your weed control program.

  • Advancements in Zoysiagrasss — Jack Fry showed of his “Innovation’ and ‘Chisholm’ turf plots – the new zoysias K-State has released. There are over 1,000 genetically different zoysias that are being evaluated at the Olathe Center.