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Tag: weed control

Herbicide Options at the time of Spring Seeding

Posted on by Jack Fry

The option for spring seeding is approaching.  Cool-season grasses may have been seeded in the winter months, or can be seeded in spring – preferably in March and April in Kansas.  Cool-season seed germination typically starts when the soil temperature reaches 50 F.  Of course, fall seeding is preferred, but we are often dealing with situations where turf quality needs to be improved with spring seeding.  One of the difficult problems is dealing with the emergence of summer annual weeds as the desired turfgrass species you’ve seeded begins to emerge. Here are herbicides that can be applied at the time of seeding to suppress summer annuals:

Tupersan (active ingredient siduron)

Siduron is a preemergence herbicide that can be used on cool-season grasses.  It does provide weed suppression, but don’t expect the same level of weed control that we get with products that are commonly used on fully established turf.  It is approved for used on colonial bentgrass, creeping bentgrass, Kentucky bluegrass, perennial ryegrass, tall fescue.  To view a Tupersan label, CLICK HERE

Tenacity (active ingredient meotrione)

Mesotrione inhibits photosynthesis in weeds once absorbed by shoots or roots.  It originated based upon biochemicals observed in the plant called bottlebrush (Callistemon citrinus).  It suppresses weeds as they absorb the herbicide at time of emergence and can also be used as a postemergence product.  Midwest grasses for which it is labeled include buffalograss, Chewings fescue, creeping red fescue, hard fescue, Kentucky bluegrass, perennial ryegrass, and tall fescue.  To view a Tenacity label, CLICK HERE

A number of other herbicides can be used once turfgrass reaches a point of maturity after seeding.  Find more details about postemergence herbicides that can be used after seeding, and all information about turf weed by getting a copy of the 2022 edition of Turfgrass Weed Control for Professionals

Find more information on weed control by clicking on the tags on the blog (left column), such as “weed control,” “crabgrass,” etc., or search by category on the right side of the page.

***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.***

New Publication: Industrial Weed Control

Posted on by Brooke Garcia

By Brooke Garcia

Visit the KSRE Bookstore to view the updated publication on Industrial Weed Control, which has a focus on right-of-way and industrial areas. This publication will describe how to manage weeds in the following areas:

  • near or around buildings
  • roads and roadsides
  • industrial sites and areas

“Excess vegetation can obstruct road visibility, create fire hazards, impair drainage, and reduce the useful life of structures. Reliability and public safety across rights-of-way and industrial areas require controlling unwanted vegetation.”  ~ Frannie Miller & Sarah Lancaster 

Get the PDF copy of the publication here: Industrial Weed Control 

Don’t Moss with Me

Posted on by Jack Fry

Silvery thread moss has been an increasing problem on golf course putting greens over the past couple of decades.  Moss is a bryophyte, and that makes it different from most plants.  It doesn’t have roots, but rather rhizoids that serve as an anchor, but aren’t as efficient at absorbing water and nutrients compared to roots.  It also grows across a wide range of temperatures.  It can be actively growing when creeping bentgrass or annual bluegrass appears dormant in late fall or early spring.  It can also experience severe drought for months (or years), and regrow once water returns; no other weeds we deal with in turf are that resilient.  Research was done on silvery thread moss over several years at K-State by graduate students Dr. Cole Thompson (now Director of Research for the USGA) and Dr. Zane Raudenbush (Dr. Raudenbush just left The Ohio State University to join Davey Tree Company).  Here are some things to know regarding how management of putting greens will influence moss that came from their research:

Things that make it happier:

  • Mowing lower promotes more moss encroachment. For example, research showed that mowing at 0.125 in vs. 0.157 in resulted in greater moss populations.
  • Areas that are thin are susceptible to moss encroachment, so maintain turf density.
  • Moss loves water. If you’re watering frequently, you’ll favor its growth.
  • Soluble nitrogen applied as a liquid on a frequent interval (spoon feeding) encourages the growth of moss.

Things that help suppress it:

  • Mow higher and maintain turf density.
  • Water less frequently while still meeting the needs of the turf.
  • Fertilize with granular products that allow slower N release.
  • Core aerify, verticut, and topdress. Although some may think they could spread moss with cultivation, research has shown that moss populations can be reduced by these practices, which is due in part because the moss colonies are disturbed and allow creeping bentgrass to occupy those areas.
  • Apply products for moss suppression. The most popular product used for this is Quicksilver, which contains the active ingredient carfentrazone-ethyl and is labeled for use on greens.  Follow the label on Quicksilver for effective moss suppression (don’t expect complete control); using this or other products labeled for moss in combination with aforementioned cultural practices will be the best approach.

Here are some useful resources on moss:

An article on the K-State webpage that give more information on moss biology and control:  https://www.plantpath.k-state.edu/extension/documents/turf/moss_2015.pdf

A video by Dr. Zane Raudebush, former K-State graduate student who conducted research on moss here and as a faculty member at The Ohio State University:  https://www.turfnet.com/turfnet-tv.html/winfieldtv/raudenbush_silvery_thread_moss/

A summary of the research Dr. Raudenbush did at K-State in Golf Course Management magazine:  https://www.turfnet.com/turfnettv.html/winfieldtv/raudenbush_silvery_thread_moss/

Some specifics regarding N fertilization and moss:

https://www.golfdom.com/nitrogen-fertilization-and-silvery-thread-moss/

***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 the K-State Turf and Landscape Team 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

NEW – Turfgrass Weed Control for Professionals – 2019

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

With new herbicides entering the market, new techniques for controlling weeds, and with more and more difficult to control weeds the “Turfgrass Weed Control for Professionals” manual has been updated to address many of these issues.  Check out the 2019 edition!  It is a must have for every turfgrass manager!

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

 

White Clover Control

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

School is starting back and college football is right around the corner.  This tells me it is the best time of the year to start renovating, overseeding or establishing new cool-season turfgrass areas. But before you do that, you might have some unwanted weeds to get rid of.  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.

Always remember a healthy turfgrass stand through proper maintenance is the best weed control and can help minimize clover 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

Yellow Nutsedge Control

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

As I talk to turfgrass professionals across the state I hear that some are getting plenty of rain while others are getting none. This time of the year we think that if we are getting some precipitation we will have yellow nutsedge popping up everywhere. Well that is not always true. Yellow nutsedge does favor moist soils but it can also grow in well-drained sites.

One of the easiest ways to identify yellow nutsedge is by a couple special features;

  • erect
  • persistant
  • yellow inflorescence
  • gradually tapering leaves to a sharp point
  • tubers not in chains
  • triangular stem

To control yellow nutsedge, if you can get applications out before tuber production then you will see increased control.  But beware, yellow nutsedge will continue to grow as long as the environment is favorable for growth, so more than one application maybe necessary.

If using a herbicide application timing is critical.  During mid summer yellow nutsedge starts making tubers and if you apply herbicides before tuber production you will get better control.  If you wait until the yellow nutsedge is big and starting to make tubers then you will be playing catch-up all year. So sooner is better.  Don’t wait for it to get too big.

Here are some options for yellow nutsedge control for turfgrass professionals;

  • sulfentrazone
  • halosulfuron
  • iodosulfuron
  • mesotrione
  • bentazon
  • triflozysulfuron
  • flazasulfuron
  • sulfosulfuron

There are many different products out there that contain these active ingredients so just make sure you have an active ingredient that has yellow nutsedge control! Also make sure you check for turfgrass tolerances.

****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