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Tag: glyphosate

Bermudagrass Control Options for Reseeding

(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.***

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Orchardgrass control, or lack of?

(By Jared Hoyle; KSU Turfgrass Research and Extension)

Last night while cruising through Facebook I can across a blog that Dr. Nick Christians from Iowa State wrote about orchardgrass.  Take a good look at the pictures because you might have some in your lawn too.

https://www.extension.iastate.edu/turfgrass/blog/orchardgrass-dactylis-glomerata-lawns

Now controlling orchardgrass is a different story.  Just because we can identify it doesn’t always mean it is easy to control.  Unfortunately, there no selective control options that we can use in cool-season turfgrass systems.  Many different chemistries (mesotrione, chlorosulfuron, metsulfuron, and more) have been tested at Purdue but didn’t even provide satisfactory control.

So with that being said the options out there right now are physical removal, blah… Or non-selective herbicides like glyphosate.

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

Non-Selective Bermudagrass Removal

(By Jared Hoyle, KSU Turfgrass Research and Extension)

For the short time I have been in the turfgrass business, I always get asked the question, “How do I kill bermudagrass?”  And before I can give the recommendation of multiple applications of glyphosate (≥ 3 lbs ae/gal) at 3 qts/A over the growing season (May, July, and September) and waiting three to four weeks for regrowth before making the follow up application, I get the response “That doesn’t work.”

To help out you can add 24 fl oz of fluazifop (Fusilade II) to the tank and it will help with bermudagrass control over the glyphosate application alone.  Remember that fluazifop has some soil residual so it can stay in the soil for some time.  So, wait 30 days before reseeding if you apply it to bare soil or 14 days if you apply it to turf. But I would still get  the response “That doesn’t work.”

Well, I got to talking with a couple of turfgrass managers about this application process and started to ask the question, “What if we are wanting to renovate during the Spring?”

Research in the past has resulted in better control with perennial broadleaf weeds, like dandelions, in the Fall compared to Spring applications. So after a little brainstorming we decided to apply this concept to controlling bermudagrass before dormancy.  This way the bermudagrass would have the dormant look throughout the winter but would be ready for renovation in the Spring.

Research Trial Location Stagg Hill (October 3, 2013)

Research was conducted at Rocky Ford Turfgrass Research Center and Stagg Hill Golf Course in Manhattan, KS to determine bermudagrass control with glyphosate, mesotrione, and fluazifop applications prior to dormancy.  Applications were made on October 3, 2013.  Treatments consisted of a non-treated control, glyphosate (6 pt/A), mesotrione (8 oz/A), fluazifop (24 fl oz/A), glyphosate (6 pt/A)+ mesotrione (8 oz/A), glyphosate (6 pt/A) + fluazifop (24 fl oz/A), mesotrione (8 oz/A)  + fluazifop (24 fl oz/A), and glyphosate (6 pt/A)+ mesotrione (8 oz/A) + fluazifop (24 fl oz/A).  All treatment included at 0.25% V/V non-ionic surfactant (NIS).  All treatments were 100% brown (dormant) bermudagrass by October 31, 2013.

Rocky Ford Trial Location (October 17, 2013)

What we found initially is that there were drastic differences between these two locations.  Bermduagrass control at the Stagg Hill location out performed the Rocky Ford location.  We believe this was due to the differences in bermudagrass cultivars.  The Rocky Ford Location was ‘Midlawn’ bermudagrass and the Stagg Hill location is a common bermudagrass.

Rocky Ford Trial Location (May 14, 2014)

At Rocky Ford the untreated control reached 100% bermudagrass cover on June 12, 2014.  At that time treatments that included glyphosate resulted in <18% bermudagrass green cover.  On June 13, 2014 the untreated control at Stagg Hill was 100% green bermudagrass cover.  All other treatments that included glyphosate resulted in <9% green bermudagrass cover.

What is really surprising is the rating that was conducted just a couple of days ago. At Rocky Ford all bermudagrass treatments recovered to at least 90% green bermudagrass cover by July 14, 2014.  But the Stagg Hill location is still showing significantly more control.  Glyphosate, glyphosate + fulazifop, glyphosate + mesotrione, and glyphosate + mesotrione + fluazifop resulted in only 27%, 26%, 17%, and 23% green bermudagrass cover, respectively.

Rocky Ford Location (June 3, 2014)

These results suggest that a single application of glyphosate in the Fall prior to bermudagrass dormancy can aid in non-selective bermuagrass removal.  We are going to repeat these trials again this year along with trying some Spring applications in combination to see if we can increase bermudagrass control.

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 http://www.facebook.com/KSUTurf