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K-State Turfgrass

Author: Brooke Stiffler

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.

The Star-of-Bethlehem makes an appearance….

By Brooke Garcia (Modified original post written by Dr. Jared Hoyle)

Photo taken by Brooke Garcia

Recognize this weed? This time of year, we are beginning to see a lot of star-of-bethlehem popping up in lawns throughout Manhattan, KS. In my neighborhood, which is one of the oldest areas in Manhattan, it seems to be in every lawn. We struggle with this particular weed every year in our turf, as well as our landscape beds.

Photo taken by Brooke Garcia

It is a very pretty plant with showy, 6-petaled white flowers that have a distinct green stripe underneath. It is a perennial bulb that sometime appears to look like clumps of grass. It can be hard to spot in a freshly-fertilized, green lawn. The green hues blend together. The leaves are linear and smooth, flat in cross-section and have a with midrib.

This plant likes shady and moist areas of the lawn, but I have also seen it grow in the sunniest locations of my lawn too. With the recent moisture and more on the way we are not short of moist areas in the lawn around Manhattan right now.

Although it is has very distinctive characteristics it can be confused with other plants that are commonly found in lawns; crowpoison (Nothoscordum bivalve),spring beauty (Claytonia virginica), wild garlic (Allium vineale) and wild onion (Allium canadense).

If you do not have a lot of this weed in your turf or landscape beds, it can be effective to hand-dig the plant and bulb completely out of the affected area. However, the leaves tear quite easily. Thus, it can be difficult to completely eradicate the entire plant using the hand-removal method.

For chemical control there are couple of options.  Both sulfentrazone and carfentrazone have shown to be very effective.

For additional information about Star of Bethlehem, see the recent post written by Ward Upham:

Wild Onion, Wild Garlic, and Star-of-Bethleham

***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.***

Great Article on Atrazine and Simazine!

By: Brooke Garcia

NC State recently wrote up an article called, Are Changes Coming for Atrazine and Simazine?” 

Both Atrazine and Simazine were reviewed in 2013, and there are proposed changes for using each of these. To learn more, visit the article.

Full Reports for each pesticide can be found in the following links:

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. 

National Pesticide Safety Education Month

By: Frannie Miller

Did you know there are about 1 million certified pesticide applicators in the United States? There is somewhere between 11,000 to 15,000 pesticide products registered for use in each state. Common consumer products that contain pesticides include flea collars, weed and feed, and roach baits. Pesticides play an important role in improving the quality of food and feed yields. They also protect the public health, controlling pests in our homes, turf, forests, waterways, and right-of-way.

February is National Pesticide Safety Education Month, which is important in raising awareness and support for land-grant Pesticide Safety Education Programs (PSEP). Pesticide Safety Educations Programs like the one at Kansas State University deliver pesticide applicator trainings on safe use of pesticides in various settings, as well as deal with state-specific needs and laws.

Have you ever wondered how safe you are when using pesticides? You can take a self-assessment of personal pesticide safety practices to evaluate where you could do better:

Self-Assessment of Personal Pesticide Safety Practices

Ice, Ice Baby.

By Dr. Jack Fry

Ice can cause many problems for turf, in various forms.

Ice Inside the Plant

Ice routinely forms inside plants when temperatures drop below freezing. Where the ice forms is important – when it’s outside the plant cells, it’s usually not an issue. This is called extracellular freezing.  However, no plant cell will survive when ice forms inside it.

The most important part of the turfgrass plant regarding survival is the crown, or growing point. Again, ice forming outside cells inside the crown is common and usually not harmful. It can become an issue, primarily in warm-season grasses, like bermudagrass, when temperatures are very cold for extended periods of time. This forces water inside cells to exit toward the ice (a matter of physics), and too much water leaving the cells will cause dehydration, which can cause the crown to die.

Freezing injury on bermuda is caused by ice forming outside cells within the crown of the plant that causes dehydration.

Ice formation inside cells of the crown commonly causes the death of grasses in the northern U.S, and it’s called intracellular freezing or crown hydration injury.  Usually, grasses that succumb to this type of injury become well hydrated in early spring, often growing in low areas that don’t drain well. Hydrated crowns that are then subjected to extremely low temperatures often suffer from ice formation inside cells of the crown;  when this occurs, they don’t survive. This is common in the northern U.S. on annual bluegrass on golf greens. It could also occur here, but would be most likely on warm-season grasses lying in low areas.

Ice Covering the Plant

Fortunately, in the central U.S., we don’t deal with extended periods of ice cover on turf. Ice cover can result from sleet, freezing rain, or snow melting and refreezing. Turf managers in the northern U.S. begin to worry about ice cover when it remains in place for about 60 days. That’s usually the limit for annual bluegrass – being under ice cover more than that can cause issues with lack of oxygen and/or accumulation of toxic gases under the ice

Ice on the Leaf Surface – Frost!

In a humid environment, when the leaf surfaces cool to temperatures below freezing, ice will form as frost on the leaves. Leaves of cool-season grasses tolerate frost on leaves just fine. Leaves of warm-season grasses don’t like frost, and we often see them go dormant shortly after the first hard frost in the fall.

Frost on the leaf surface can damage when foot or vehicle traffic causes the crystals to puncture the leaf cells (photo courtesy of Dr. Hoyle).

Frost is primarily a problem for turf managers in spring and fall on cool-season grasses. Foot or vehicle traffic pushes the ice crystals through the leaf surface and punctures cells, causing them to collapse. The result is that there is often brown turf where traffic was present. Honestly, I don’t think we know enough about the physics of ice that comprises frost, and I suspect that frost differs a lot – some ice forming on leaves may be more damaging than other ice.

Following are a few articles related to frost on turf.

For golfers:

https://www.usga.org/content/usga/home-page/articles/2018/01/5-things-to-know–frost-delays.html

For superintendents managing golf courses:

https://www.golfcourseindustry.com/article/golf-frost-delay

Apparently, in Japan, golfers play year-round regardless of temperature.  Some courses ignore frost to sustain income and have had less damage than expected:

https://www.blog.asianturfgrass.com/2016/12/how-to-lose-120-million-yen-with-frost-delays.html

 

Seeding Tall Fescue in January? Sure!

By Dr. Jack Fry

Identifying seeding windows for cool-season grasses,  like tall fescue, in our region is often difficult because weather is so different year to year.  For example, for autumn seeding, October 15 is often suggested as the deadline for seeding in northeast Kansas.  Seeding after that date doesn’t mean that there won’t be success – some years there may be, others year not.  The concern is that germination and emergence may still occur after mid-October.  However, the seedling that emerges may not mature to a point where it can survive the cold, dry conditions common during Midwest winters.

Following the mid October deadline, the next window for seeding opens around Thanksgiving and continues into March.  We call it “dormant” seeding.  Dormant seeding means that the grasses out in the lawn now are dormant and not growing.  In addition, the seed you scatter in mid-winter will also remain “dormant” until warmer conditions and moisture return in the spring.  Unfortunately, some of us remain dormant until spring as well – outdoor work in midwinter may not sound attractive.  Tall fescue germination is optimized between soil temperatures of 59 and 72 F, so seed applied in winter will remain inactive in the soil until it warms to near 60 F, and it will then begin to germinate.  Other grasses are also candidates for dormant seeding as well, including other species of cool-season grasses, buffalograss, and bermudagrass.

Seed-to-soil contact is critical.  If conditions are dry, vertical mowing or slit seeding may be possible.  In addition, a light topdressing of soil applied over seed can also maximize seed-to-soil contact.  Seeding on frozen soil is also possible, and seed-to-soil contact is improved as the soil thaws and freezes, which creates cracks in the surface in which seed can lie.  Covering or mixing seed with the soil, where it will likely remain for a number of weeks before germination, also prevents it from being a source of food for birds and rodents.

Twenty years ago, Ward Upham, Extension Associate in Horticulture and Natural Resources, did a study to evaluate dormant seeding month effects on tall fescue cover in May.  He seeded plots on the 15th of each month from December through March onto bare soil that had been tilled and raked.  On May 18, plots seeded in February and March each had an average of 80% coverage.  December and January seedings were each at about 60% coverage.  Ward suspected that having seed out in the environmental longer made in subject to erosion and consumption by animals.

Advantages to Dormant Seeding:

  • Sometimes it is drier in mid-winter than early spring, which allows outside work to be done. Seeding in April and May can be difficult months for seeding during frequent rainfall.
  • Spring emergence will occur at the earliest possible date.
  • There may be more time and labor available now that’s not available in the spring.

Disadvantages to Dormant Seeding:

  • Weather doesn’t always cooperate, and midwinter may be too wet to get it done. However, if just small areas are needing seed, that can be done by hand.
  • Stand establishment may not be as successful as seen with autumn seeding, the preferred time. And, just like spring seeding, weed competition will be greater as the stand matures.
  • Preemergence herbicides applied in late fall or in spring may inhibit germination and growth of the seedlings. Preemergence herbicides that can be used in the tall fescue seedbed include siduron (Tupersan) and mesotrione (Tenacity).

Thank you for a wonderful Turfgrass Conference!

By: Brooke Garcia

We would like to THANK YOU for attending the 69th Annual Kansas Turfgrass Conference in Manhattan, KS!

This three day conference was hosted in Manhattan, KS on December 4th, 5th, and 6th. The conference is hosted by the Kansas Turfgrass Foundation, in conjunction with KNLA. This was the first year this conference was located in Manhattan, and we have received a lot of great feedback. Thank you to everyone who shared their input. We appreciate all of our participants who were able to attend, learn, and grow at this conference.

We would like to especially thank our featured speakers. They are pictured above from left to right (From Left: Dr. Josh Friell, Dr. Frank Wong, Dr. Roch Gaussoin, and Dr. Matthew Elmore). In addition to our featured speakers, we had a variety of sessions that were led by university faculty, companies, and leaders in the turf industry. Whether you’re new to the turf industry or a seasoned professional, everyone was provided with an opportunity to learn something new.

In addition, we would like to express our gratitude to all of our vendors who participated in the conference, as well as offered their sponsorship. Thank you for taking your time to network with the many participants who attended the conference.

Thank you for a wonderful way to end the year! Happy Holidays!

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:

It’s beginning to look a lot like…. Christmas!

By Brooke Garcia

In the greenhouses at Kansas State University, I couldn’t help but notice the beautiful poinsettias growing. This isn’t the first place I have seen them around town, as garden centers and grocery stores are stocking up as well. However, the poinsettias currently at K-State are truly unique varieties. Who knew there were pink poinsettias? I had no idea!

The 1200 poinsettias featured in the K-State greenhouses are used for both research and teaching purposes. There are 37 students currently enrolled in Dr. Kimberly Williams’ Greenhouse Operations Management course, and they produce these poinsettias to learn more about managing plants in a greenhouse environment. The poinsettias featured below are just a few of my favorites: 

Christmas Traditions                                          Ferrara   

         

Golden Glo                                                    J’Adore Pink

Mars White                                               Premium Marble

Premium Picasso                                     XMas Beauty Marble

Many of these poinsettias will be included in the “Friends of the KSU Gardens Annual Poinsettia Sale” in the KSU Gardens Quinlan Visitor’s Center, located in Manhattan, KS. The dates for the sale are listed below:

  • Nov. 22, 2019: 12:00-5:30pm
  • Dec. 4th, 2019: 3:00-5:30pm
  • Dec. 6th, 2019: 11:30am-2:00pm

The poinsettias are in a 6.5 inch pot for $10.00 each. There will also be 10″ Centerpieces sold for $15.00. Cash or check only; no credit cards.

For more information about poinsettias, be sure to check out the two new articles on the Horticulture e-Newsletter blog. Link to the individual articles below: