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K-State Turf and Landscape Blog

Category: Weeds

Wild Violet Control

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Wild violet or common blue violet is a persistent perennial broadleaf weed commonly found in thin, shaded turfgrass. The plant has heart-shaped, shiny leaves and can spread by rhizomes which makes it a difficult to control weed. The flowers are deep purple or bluish purple. There are many similar species but collectively, turfgrass managers just refer to them as wild violet.

Control has been difficult but can be achieve if you choose the right herbicide and rate. Triclopyr has proven to be effective in cool-season turfgrass and is contained in many different products that are on the market. But the key is to make sure that you apply more than 0.5 lbs ae/A of triclopyr to result in effective control. Not all products that contain triclopyr when applied at the recommended rate will have enough triclopyr for effective control.

At a quick glace through the Turfgrass Weed Control for Professionals manual (Get you copy here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239) I found a table that shows the rates of triclopyr-delivered by various products at the low and high label rate. From that chart, the following are products that contain ≥ 0.5 lbs ae/A of triclopyr, when applied at the correct rate.

  • Aquasweep
  • Chaser 2 Amine
  • Chaser
  • Crossroad
  • Everett
  • Confront
  • 2-D
  • Tailspin
  • Turflon Ester Ultra
  • Triclopyr 4
  • Trycera

The take home message; To control wild violet in cool-season turfgrass use tricopyr (0.5 lbs ae/A), may different products contain triclopyr, not all products contain enough triclopyr, choose a product that when applied at the correct rate will result in at least 0.5 lbs ae/A of triclopyr.

If you are needing to control wild violet in bermduagrass or zoysiagrass; metsulfuron, sulfentrazon + metsulfuron and flazasulfuron are effective. Repeat applications are often required regardless of the herbicide.

Also, fall applications are best followed by spring applications.

Information from this post if from “Turfgrass Weed Control for Professionals” To get your copy today click here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

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

White Clover and Yellow Woodsorrel Control

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

White clover is one of the most common weeds found in cool-season turfgrass.  It can grow in a wide range of environmental conditions and can tolerate many of our cultural practices.   It can also spread by seeds and by stolons. White clover is a perennial broadleaf weed that has trifoliate leaves that may or may not have a wedged-shaped mark. Although it is called white clover the flowers are white but may turn pink as they age.

Because white clover can fix its own nitrogen some see it as an important species to add beneficial soil nitrogen.  There had been some work done to explore using both clover and turfgrass in a mixture in their lawns.  Others may consider it as a weed.

If you consider it a weed, fall is a great time to try and control it.  But did you know 2,4-D, glyphosate and sulfentrazone do not control white clover?

For best control herbicides that contain clopyralid, dicamba, fluroxypyr, florasulam, metsulfruon, and/or quinclorac (also controls crabgrass) provide the best control when applied in the fall.

Yellow woodsorrel (Oxalis stricta) is a perennial or annual broadleaf weed that has clover-like trifoliate heart shaped leaves.  Yellow woodsorrel most commonly spreads by seeds that are contained in a capsule that when it explodes ejects the seeds.  It can be confused with clover but has yellow flowers with five petals.  You can find this weed in a wide range of soil conditions and can commonly be confused with black medic, birdsfoot trefoil and white clover. A similar species is creeping woodsorrel but it is most commonly found in landscape plantings while yellow woodsorrel is most commonly found in turf.

To control oxalis, herbicides that contain triclopyr and fluroxypyr are very effective.

Herbicides that contain fluroxypyr include;

  • Battleship III
  • Escalade 2
  • Momentum FX2
  • Tailspin
  • Vista XRT

Herbicides that contain triclopyr include;

  • 2-D
  • 4-Speed XT
  • Battleship III
  • Chaser
  • Chaser 2 amine
  • Confront
  • Cool Power
  • Eliminate
  • Horsepower
  • Momentum  FX2
  • Tailspin
  • Three-Way Ester II
  • Turflon Ester Ultra
  • Turflon II amine
  • Triclopyr 4
  • TZONE

Always remember a healthy turfgrass stand through proper maintenance is the best weed control and can help minimize clover and yellow woodsorrel in you turfgrass.

Information from this post if from “Turfgrass Weed Control for Professionals” To get your copy today click here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

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

K-State turfgrass specialist urges mid-summer checkup on lawns

Posted on by Brooke Garcia
Many Kansas landscapes include warm-season grasses, which require a little care in order to stay healthy during the hot summer months.

Hoyle says warm-season grasses may need fertilizer to remain healthy

MANHATTAN, Kan. – Kansas State University Associate Professor and Extension Turfgrass Specialist, Dr. Jared Hoyle says homeowners ought to be thinking about a mid-summer checkup on their lawns, which likely includes applying fertilizer and weed killer.

Many Kansas summer landscapes include warm-season grasses, namely bermudagrass, zoysiagrass and buffalograss. Each of those requires a little care in order to stay healthy through the hot weeks ahead.

“Those three grasses are not all created equal and some grow faster than others, which means we need to feed them a little bit different,” said Hoyle, an associate professor in the Department of Horticulture and Natural Resources.

For bermudagrass and zoysiagrass, Hoyle suggests applying a total of 1-3 pounds of nitrogen per 1000 square feet during a typical growing season, which is the beginning of May through the middle of August.

“You can split that up into multiple applications of a quick release fertilizer, or you could do fewer applications of a slower release,” he said. “But the main goal is 1-3 pounds of nitrogen per 1000 square feet regardless of what number or percentage product you’re using.”

Buffalograss does not require as much nitrogen. Studies at Kansas State University indicate that “about 1 pound of nitrogen per year for 1000 square feet is good,” according to Hoyle.

“It’s hard to split up a pound over multiple applications, so that’s one where you might want to look at a slow release to put that pound of nitrogen per 1000 square feet throughout the year,” he said. “You can do that right now and that will get you through the rest of the year with a slow release fertilizer.”

In addition to fertilizing warm-season grasses, Hoyle said homeowners should be looking at ways to control thatch and weeds in the lawn.

“We really like to preach that if you are going to do something with the lawn — whether it is fertilizing or watering — do it when it’s actively growing,” Hoyle said. “Right now, with warm-season grasses, if you have a thatch problem, you can tear that area up (with a verti-cutter or slicer), fertilize the lawn, and it will grow right back in. If you try to do that during the fall or spring months, there will be periods of time when the lawn isn’t growing, or delayed growth, and it could lead to more problems.”

Among weeds, crabgrass and yellow nutsedge are two of the most troublesome this time of year.

““I’m seeing a lot of crabgrass and yellow nutsedge and I blame it on the weather,” Hoyle said. “Yellow nutsedge loves flooded, compacted soils and because of periodic flooding around the state, I have seen a lot of areas that typically never have yellow nutsedge. It’s a weed to keep an eye out with the weather conditions as they have been.”

To control yellow nutsedge, look for products with the active ingredients halosulfuron or sulfrentrazone, he said.

Crabgrass that has already emerged can be treated with products that include the active ingredient quinclorac.

Hoyle noted that homeowners should be patient when applying herbicides to yellow nutsedge and crabgrass; it might take more than one application to control those weeds.

K-State’s Department of Horticulture and Natural Resources publishes a weekly horticulture newsletter with updated information on lawn care and other turfgrass issues. Residents may also contact their local extension agent.

Under Attack from Weeds

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

As a turfgrass manager, as soon as you think you have it under control… BAM, you are under attack. Just in a short period of time Manhattan has been under attack from weeds. Now many of these weeds are large and hard to control.

With all the rain earlier in the season there was standing water in many of the low areas of the research farm. The turf did not like it and eventually died. But what did like it was yellow nutsedge. I put up some information about this in the recent past but, it is everywhere and I am still getting phone calls about it so I wanted to direct you to the most recent post on controlling yellow nutsedge.

https://blogs.k-state.edu/turf/yellow-nutsedge-reported-across-ks/

Also, you can use glyphosate to treat yellow nutsedge in landscape beds but it only provides marginal control. Remember not to use glyphosate to treat yellow nutsedge in your turf.

Crabgrass galore! Slow to start but it is going strong now! Anywhere we didn’t put down a preemergent herbicide this year crabgrass has started to take over. Good thing there is options for control. Check out my earlier post for crabgrass options. Pay attention to control options for larger tillered crabgrass.

https://blogs.k-state.edu/turf/postemergent-crabgrass-control-2/


If it is not yellow nutsedge or crabgrass it is goosegrass. Back in early June, goosegrass emergence was reported across Kansas. Now the goosegrass is growing and going to be more difficult to control because it has tillered out. Make sure you make your follow-up applications when recommended and choose your control options that are effective on larger goosegrass.

If you have cool-season turfgrass then you can use fenoxaprop (Acclaim Extra), fluazifop (Fusilade II), tropramizone (Pylex), or MSMA (golf courses and sod farms only!).  You will have to do more than one application since the goosegrass is tillered out.  Sulfentrazone (Dismiss) is also effective on goosegrass if it has not tillered out yet so might want to go with another option since now the goosegrass is big.

For all you golf courses out there that have creeping bentgrass fairways it is going to be a little bit more difficult because the herbicides that work best tend to injure the turf.  1-Tiller or smaller can be controlled with fenoxaprop (Acclaim Extra) at 3.5 fl oz/A but you will need to re-apply every two weeks to make sure you are applying to small plants. This could be a follow-up option if new goosegrass starts to emerge before the season it over.

As crazy as it sounds a herbicide that has commonly been used for broadleaf weeds has shown control on goosegrass.  SpeedZone (2,4-D +dicamba + MCPP) has shown control but a follow up application is going to be needed 30 days after initial application. Pay attention to the temperature restrictions in this heat!

Tropramizone (Pylex) can be used on bentgrass at lower rates (0.25 fl oz/A) but definitely need a repeat application at 21 days

Now if you have bermudagrass or zoysiagrass then you can use Tribute TOTAL (thiencarbazone + foramsulfuron + halosulfuron).  Fusilade II and Acclaim Extra that works in cool-season grass can also be used on zoysiagrass.  If you mix these products with triclopyr (Turflon Ester Ultra or Triclopyr 4) then you will get better results.

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

Information in this article is from Turfgrass Weed Control for Professionals.

Patton, A.J., M. Elmore, J. Hoyle, J. Kao-Kniffin, B. Branham, T. Voigt, N. Christians, A. Thoms, G. Munshaw, A. Hathaway, T. Nikolai, B. Horgan, L. Miller, X. Xiong, W. Kreuser, R. Gaussoin, D. Gardner, Z. Raudenbush, D. Li, P. Landschoot, D. Soldat, and P. Koch. 2019 Turfgrass Weed Control for Professionals. Purdue University Extension Publication. TURF-100. pp. 128.

Get your copy here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

***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

Developing a Weed Control Program

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

There are many important factors to consider when you are developing a weed control program.  Here is a list of information you should have to help you develop your program.

  1. Turfgrass species
  2. Area needing to be treated.
  3. Correct identification of the problematic weeds.
  4. The time of year the weeds are present.
  5. Determine why the weeds are invading and correct the conditions or cultural practice that are leading to the weed invasion.
  6. Select a chemical that is effective and label for control of the weeds you are treating.
  7. Follow all label instructions!!!!!!!
  8. Apply at the correct time and rate.
  9. Apply herbicides evenly.
  10. Follow up with repeat applications if recommended on the label.

This is also great information to have if you can’t figure out why a weed control method didn’t work.  For more information on diagnosing why a weed control method didn’t work, click here – https://blogs.k-state.edu/turf/i-sprayed-but-i-didnt-kill-the-weed/

Information in this article is from Turfgrass Weed Control for Professionals.

Patton, A.J., M. Elmore, J. Hoyle, J. Kao-Kniffin, B. Branham, T. Voigt, N. Christians, A. Thoms, G. Munshaw, A. Hathaway, T. Nikolai, B. Horgan, L. Miller, X. Xiong, W. Kreuser, R. Gaussoin, D. Gardner, Z. Raudenbush, D. Li, P. Landschoot, D. Soldat, and P. Koch. 2019 Turfgrass Weed Control for Professionals. Purdue University Extension Publication. TURF-100. pp. 128.

Get your copy here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

***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

Bermudagrass Control Options for Reseeding

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Last week Ward Upham wrote an article on bermudagrass control in the KSU Horticulture Newsletter.  In the article below he explains the difficulty of controlling bermudgrass, the process and the multiple applications of a non-selective herbicide.

Bermudagrass Control by Ward Upham

Bermudagrass can make a nice lawn if you don’t mind its
invasiveness and short growing season. But many people dislike both
these characteristics. Warm-season grasses, such as bermudagrass,
zoysiagrass and buffalograss, green up later than cool-season grasses
such as tall fescue and Kentucky bluegrass. They also go dormant earlier
in the fall, which can make a lawn unattractive. Bermuda that invades a cool-season lawn will be brown during much of the spring and fall while the tall fescue portion of the lawn is green. Bermuda is much more drought and heat resistant than cool-season grasses, so it will take over a cool-season lawn during the summer months if it is in full sun.

So, how do you control bermudagrass that has invaded a cool-season
lawn? Research conducted in 1996 showed that glyphosate is the best herbicide for the job. Glyphosate is a nonselective herbicide and will kill everything—
including tall fescue or Kentucky bluegrass. Therefore, you will need to
reseed treated areas. In our study, we applied a 2% solution of
glyphosate on July 15 and again on August 15 on a bermudagrass plot that
was more than 15 years old. More than one year later, we saw no
regrowth. Glyphosate works best if bermuda is growing well. The better
the bermudagrass is growing, the more chemical is taken up and pushed
into the roots. Water and fertilize if needed to get it going.
Spray about the middle of July (or when the bermuda is growing
well). Use glyphosate (2% solution). Wait two weeks and scalp the lawn
(mow as low as possible and remove clippings.) This will prevent dead
grass from covering any bermuda that starts to recover. Wait another two
weeks and spray again with glyphosate if there is any green. Wait two
more weeks and reseed. (Ward Upham)

(For the KSU Horticulture Newsletter click here – https://hnr.k-state.edu/extension/info-center/newsletters/index.html)

But during this time areas are dead, may not be acceptable and re-seeding must be done in the fall.  What if you are wanting to seed in the spring (Especially if you ware wanting to convert to buffalograss)? This process might not work due to the timeline. Therefore, a couple years ago we looked into some other options and combinations for bermudagrass control. Here is a brief overview of the project.

Multiple summer applications of glyphosate are commonly recommended for bermudagrass (Cynodon spp.) control. However, this regime results in an extended period of displeasing and nonfunctional turfgrass, and is not ideal for spring establishment. An autumn glyphosate application prior to winter dormancy can control bermudagrass and may benefit spring  establishment projects. However, research is needed to more precisely define the parameters of efficacious late-season herbicide applications for bermudagrass control as it transitions into dormancy. Therefore, our objective was to examine late-season bermudagrass removal using combinations of glyphosate, fluazifop, and mesotrione. Experiments were initiated in October 2013 at the Rocky Ford Turfgrass Research Center in Manhattan, KS, on mature ‘Midlawn’ hybrid bermudagrass, and at Stagg Hill Golf Course in Manhattan, KS, on mature common bermudagrass. Seven herbicide treatments containing combinations of glyphosate, fluazifop, and mesotrione were evaluated. Green bermudagrass cover (0–100%) was visually estimated when treatments were applied and every 14 d after application. Only treatments containing glyphosate reduced the green cover of bermudagrass at each site the following year. Across all ratings dates and locations, adding mesotrione, fluazifop, or both to glyphosate did not further reduce green bermudagrass cover. Overall, results indicate that a single autumn application of glyphosate prior to bermudagrass dormancy reduces bermudagrass cover the following spring. The significant reduction at spring green-up may allow turf managers to make additional applications in the spring for increased control before spring establishment.

For the full article;

Hoyle, J.A.,C. Braun, C.S. Thompson and J.A. Reeves. 2018. Late-Season Bermudagrass Control with Glyphosate, Fluazifop, and Mesotrione Combinations. Agrosystems, Geosciences & Environ. 1:180014 (2018) doi:10.2134/age2018.06.0014

https://dl.sciencesocieties.org/publications/age/pdfs/1/1/180014

***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

I sprayed but I didn’t kill the weed!

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

“I sprayed but I didn’t kill the weed!” I get this comment many times throughout the year and there could be may possible reasons why, other than saying that herbicide doesn’t work. What I have found is that the most common reason is human error. So, here are a couple questions you should ask yourself to help determine what went wrong.

  1. Did you correctly identify the weed?
  2. Was the weed listed on the label?
  3. Did you use the correct rate?
  4. Did you have uniform spray coverage?
  5. Did you apply it at the appropriate growth stage?
  6. What was the temperature when you applied? Was it within the label recommendation?
  7. Was there adequate soil moisture for weed growth?
  8. Did you tank-mix?  Could have an antagonistic effect!
  9. Where you suppose to make two applications (according to the label)?
  10. Did it rain or did the irrigation run soon after application?
  11. Did you add an adjuvant or surfactant that was recommended on the label?
  12. If you applied a PRE, did you water it in, within the next few days? or has the weed already germinated or emerged?

These are just a couple questions used to help figured out what happened if you sprayed and didn’t kill the weed.

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

Postemergent Crabgrass Control

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Today I was walking around the Rocky Ford Turfgrass Research Center in Manhattan, KS looking for an area to put out a postemergent crabgrass study and notice that the crabgrass on the research farm is all different stages.  It is important to know what stage the crabgrass is in to help with control.  That could determine your success in controlling it with postemergent herbicides

There are postemergent herbicide options out there for crabgrass control.  But depending on how big or how many tillers the crabgrass has will help you determine what product to use.  First, determine the size or stage of crabgrass you have present.

Here is a picture to show the tillering stages of crabgrass.

The smaller the crabgrass the easier it is to kill it.  The tillered crabgrass may take more than one application and higher rates so make sure you check the label for correct application rates and intervals.

  • dithopyr – Can provide control to crabgrass up to one tiller stage.  This product also has preemergence activity.
  • quinclorac – Can be applied on most cool- and warm-season turfgrass species.  This product controls crabgrass when it is one tiller or smaller or when it has four or more tillers.
  • mesotrione – Can be effective for crabgrass control but in most cases will take two applications at two week intervals. The label also states that applications must be made before the four tiller crabgrass stage.
  • topramazone – Similar to mesotrione, this product will require two applications at three week intervals. Use at higher rates on crabgrass that have greater than one tiller.
  • fenoxaprop – Are very effective in controlling crabgrass.  Label states that this product can be applied to annual grasses up to the five tiller stage. Remember not to tank mix with products that contain 2,4-D, antagonism can occur.

As one last reminder, do not apply post emergent herbicides outside the recommended temperature on the label.  This will increase the risk of turfgrass injury.

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

Research UPDATE – Influence of Herbicide Combinations and Sequential Applications on Windmillgrass (Chloris verticillata) Control

Posted on by jahoyle

(By Nic Mitchell and Jared Hoyle, KSU Turfgrass Research and Extension)

Windmillgrass (Chloris verticillata Nutt.) populations commonly infest turfgrass systems in the mid-west, which result in aesthetically unacceptable turfgrass stands. Windmillgrass is a perennial monocot bunch-type grass. It often spreads by stolons and by its panicle shape seed which acts much like tumble weed.

Prior research found that Pylex (topramezone) and Acclaim Extra (fenoxaprop) result in fair to minimal control of windmillgrass with a single application. Tenacity (mesotrione) which, labeled for two applications for best control of windmillgrass, recommends the second application should be three weeks after initial application. Additionally, studies have shown the addition of triclopyr to HPPD inhibitor herbicides increases windmillgrass control in a controlled environment.

The goal of this research was to determine the effect of a sequential postemergent herbicide applications and the addition of triclopyr to HPPD inhibitors herbicides on windmillgrass control.

Research trials were initiated in 2018 at Rocky Ford Turfgrass Research Center in Manhattan, Kansas. Windmillgrass was infested in a low maintenance tall fescue (Schedonorus arundinaceus) system. Seven herbicide combinations were applied as a single application or with a sequential application and non-treated control was included for comparison for a total of 15 individual treatments. All herbicide treatments were applied on August 16, 2018 and treatments that received a sequential application were applied on September 9, 2018. Herbicide treatments consisted of Pylex (topramezone) at 2 fl oz/a, Tenacity (mesotrione) at 8 fl oz/a, Acclaim (fenoxaprop) at 39 fl oz/a, Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a, Pylex (topramezone) at 2 fl oz/a + Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a, Tenacity (mesotrione) at 8 fl oz/a + Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a, Acclaim (fenoxaprop) at 39 fl oz/a + Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a, and a nontreated control. Data collection consisted of visual percent windmillgrass cover (0-100%) and were transformed to percent windmillgrass control for presentation purposes. Analysis of variance (ANOVA) was performed in SAS 9.4 (SAS Institute Inc., Cary, NC) and means were separated according to Fisher’s protected least significant difference (LSD) level at 0.05.

We found that Pylex (topramezone) applied at 2 fl oz/a resulted in 87% windmillgrass control at 8 weeks after treatment. A single application of Pylex (topramezone) at 2 fl oz/a + Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a and Tenacity (mesotrione) at 8 fl oz/a + Alligare Triclopyr 4 (triclopyr) at 32 fl oz/a resulted in 96% and 97% windmillgrass control 8 weeks after initial treatment, respectively. All treatments that received a sequential application on September 9, 2018 excluding the non-treated control and Acclaim (fenoxaprop) at 39 fl oz/a provided 100% windmillgrass control at 8 WAT. Acclaim (fenoxaprop) at 39 fl oz/a applied on August 16, 2018 followed by an application at 39 fl oz/a on September 9, 2018 resulted in 88% windmillgrass control.

Table 1. Windmillgrass (Chloris verticillata Nutt.) control 8 weeks after initial application from single and sequential applications at Rocky Ford Turfgrass Research Center in Manhattan, KS; 2018.

Treatment Herbicide Rate Application Date Controla
___%___
1 non-treatedb – – 4 Cc
2 Pylex + MSOd 2 fl oz/a + 1% v/v Aug. 16, 2018 87 A
3 Tenacity + NISd 8 fl oz/a + 0.25% v/v Aug. 16, 2018 9 C
4 Acclaim Extra + NIS 39 fl oz/a + 32 fl oz/100 gal Aug. 16, 2018 16 C
5 Triclopyr 32 fl oz/a Aug. 16, 2018 64 B
6 Pylex + Triclopyr + MSO 2 fl oz/a + 32 fl oz/a + 1% v/v Aug. 16, 2018 96 A
7 Tenacity + Triclopyr +NIS 8 fl oz/a + 32 fl oz/a + 0.25% v/v Aug. 16, 2018 97 A
8 Acclaim Extra + Triclopyr +NIS 39 fl oz/a + 32 fl oz/a + 32 fl oz/100 gal Aug. 16, 2018 63 B
9 Pylex + MSO 2 fl oz/a + 1% v/v Aug. 16, 2018 fbe Sept. 9, 2018 100 A
10 Tenacity + NIS 8 fl oz/a + 0.25% v/v Aug. 16, 2018 fb Sept. 9, 2018 100 A
11 Acclaim Extra + NIS 39 fl oz/a + 32 fl oz/100 gal Aug. 16, 2018 fb Sept. 9, 2018 88 A
12 Triclopyr 32 fl oz/a Aug. 16, 2018 fb Sept. 9, 2018 100 A
13 Pylex + Triclopyr + MSO 2 fl oz/a + 32 fl oz/a + 1% v/v Aug. 16, 2018 fb Sept. 9, 2018 100 A
14 Tenacity + Triclopyr +NIS 8 fl oz/a + 32 fl oz/a + 0.25% v/v Aug. 16, 2018 fb Sept. 9, 2018 100 A
15 Acclaim Extra + Triclopyr +NIS 39 fl oz/a + 32 fl oz/a + 32 fl oz/100 gal Aug. 16, 2018 fb Sept. 9, 2018 100 A

a Ratings were conducted 8 weeks after initial application; October 11, 2018.

b Non-treated control contained approximately 65% windmillgrass cover throughout the research trial. 4% control was observed due natural declining of windmillgrass populations to environmental considerations on October 11, 2018.

c Treatment means followed by a common capital letter are not significantly different according to Fisher’s protected LSD (α= 0.05).

d MSO, methylated seed oil and NIS, non-ionic surfactant were added to treatments according to herbicide manufacture recommendations.

e fb, followed by.

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

Warm-season Turfgrass Lawn Care Reminders

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Now that the summer weather is finally here it is time to start thinking about maintenance on warm-season turfgrass.  Below are some monthly reminders for everyone that has warm-season turf.

Bermudagrass and Zoysiagrass

May – August 15
Fertilize with 1 lb. of nitrogen per 1,000 square feet per application. Follow the recommendations on the bag. More applications will give a deeper green color, but will increase mowing and may lead to thatch buildup with zoysiagrass. Bermudagrass can also have problems with thatch buildup but thatch is less likely with Bermuda than zoysia. Bermudagrass – Use two to four applications. Zoysiagrass – Use one to two applications. Too much nitrogen leads to thatch buildup.

One Application: Apply in June.
Two Applications: Apply May and July.
Three Applications: Apply May, June, and early August.
Four Applications: Apply May, June, July, and early August.

Remember to look and see if you are using a quick release nitrogen source or a slow release nitrogen source.  If you use a quick release source then it is immediately available but only lasts a couple weeks.  Thats why you would have to make a couple of applications like it is listed above.  If you are going to use a slow release source it will tell you on the bag how long the product will last.  Therefore, you might not have to make as many applications.

So generally you want to use a total of 2 to 4lb. of nitrogen per 1,000 square feet per year for bermudagrass and 1 to 2 lb. of nitrogen per 1,000 square feet per year for zoysiagrass.

June
If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. June is a good time to core aerate a warm-season lawn. Core aeration will help alleviate compaction, increase the rate of water infiltration, improve soil air exchange and help control thatch.

Late-July through August
If you see grub damage, apply a grub killer. If Imidacloprid has been applied, this should not be necessary. Grub killers must be watered in immediately.

For more information check out the Zoyisagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1451

For more information check out the Bermudagrass Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=586

Buffalograss

June

Fertilize with 1 lb. of nitrogen per 1,000 square feet during June. More applications will give a deeper green color, but can encourage weeds. If it is felt that a second application is needed, apply in July.

If grubs have been a problem in the past, apply a product containing imidacloprid by mid July. Imidacloprid can be applied as early as mid May if there are problems with billbugs or May beetle grubs. These products kill the grubs before they cause damage. They are effective and safe but must be watered in before they become active. Again, I would only treat if grubs have been a problem in the past. Note that the whole area may not need to be treated. The beetles that lay the eggs for the grubs are attracted to lights and moist soil and those areas are most likely to be infested.

Late-July through August

If you see grub damage, apply a grub killer. If imidacloprid has been applied or if grubs have not been a problem in the past, this should not be necessary. Grub killers must be watered in immediately.

For more information check out the Buffalograss Lawns Publication at the KSRE Bookstore – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1447

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