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NIMBLEWILL UPDATE-JUNE 2012

June 14, 2012

Here is an update from answer-line person, Richard Jauron, on his nimblewill control demonstration with the herbicide Tenacity (mesotrione).  You will find posts on the application from last summer and updates during the fall of 2011 and spring of 2012 .  The following pictures are from June 2012. 

The work is going well, and he feels that he has achieved at least 75% control at this time.

Nimblewill can come back later in the season from plant parts.  It can also come back from seed.  Richard will continue to monitor this.  He also plans to keep at it until he has beat the nimblewill.
 

Here are some comments from Richard.

Nimblewill is present in the center of this photograph.  Area was treated with Tenacity in summer of 2011. 

 --- Nimblewill is present in photograph, but at a reduced level.

Overall view of the backyard.  This area contained several areas of nimblewill in 2011.  Nimblewill-infested areas were treated with Tenacity in the summer of 2011.  Seventy-five to eighty percent of the nimblewill appears to have been destroyed.  

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RICHARD JAURON'S NIMBLEWILL EXPERIMENT

November 9, 2011

Here is the next installment in the series on 'answer line person' Richard Jauron's experience with the control of nimblewill with Tenacity (mesotrione). You will find other installments from this summer and fall.

We're going to follow this until well into next year when we know how successful this has been.

FROM RICHARD JAURON:

Here is a short chronology of my experience treating nimblewill infested areas in the lawn with the herbicide Tenacity (Mesotrione). (Previous blogs on this topic were posted on July 7, 2011 and August 2, 2011.)

On Tuesday, June 28, 2011, I treated nimblewill infested areas in my lawn with Tenacity. (One-fourth teaspoon of Tenacity and three-fourths teaspoon of a non-ionic surfactant (Turbo Spreader Sticker) was added to 2 quarts of water.)

Within 2 or 3 days, the nimblewill foliage turned light green. Within 7 to 10 days, the uppermost growth turned white. (See photos 1 and 2)

At the end of 3 weeks, the lowest portions of the nimblewill were still green. Most of the upper portions of the nimblewill were white or brown. (See photos 3 and 4)

The nimblewill was treated a second time on Tuesday, July 26, 2011. (One-fourth teaspoon of Tenacity and three-fourths teaspoon of a non-ionic surfactant was added to 2 quarts of water.)

By late summer, the Tenacity treated nimblewill had turned completely brown and appeared to be dead. The following photographs were taken on September 15, 2011. (See photos 5 and 6). While the nimblewill appears to be dead, the effectiveness of Tenacity won’t be known until late spring/early summer of 2012. If any of the nimblewill has survived, it should begin to green up in late May or June.

 

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

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NIMBLEWILL CONTROL: SECOND INSTALLMENT

August 2, 2011

Here is the second installment of the July 7 post on Nimblewill control in lawns. This demonstration is being conducted by Richard Jauron, the answer line person in the horticulture department. He is using tenacity (mesotrione) to try to completely eliminate Nimblewill from his home lawn. We're going to follow this and see if Richard or the Nimblewill wins the final battle. It may take a two years before we know. The answer line number is 515-294-3108.

From Richard:
The nimblewill was initially treated on Tuesday, June 28, 2011. One-fourth teaspoon of Tenacity and three-fourths teaspoon of a non-ionic surfactant (Turbo Spreader Sticker) was added to 2 quarts of water. Nimblewill infested areas were spot-treated with the solution. Within 2 or 3 days, the nimblewill foliage turned light green. Within 7 to 10 days, the uppermost growth turned white. At the end of 3 weeks (see attached photos), the lowest portions of nimblewill were still green. Most of the upper portions of the nimblewill were white or brown. The nimblewill was treated a second time on Tuesday, July 26. One-fourth teaspoon of Tenacity and three-fourths teaspoon of a non-ionic surfactant was added to 2 quarts of water.

As of August 2, the nimblewill has turned white. We know that it can come back, however, and that it can germinate from seed in the soil in the spring. Richard will be persistent with his applications in the fall and spring. We will keep you informed of what is happening.

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NIMBLEWILL CONTROL IN KENTUCKY BLUEGRASS TURF

July 7, 2011

Nimblewill (Muhlenbergia schreberi ) is a warm-season perennial grass with a fine texture and a gray-green color. It spreads by stolons and forms a dense matt in cool-season lawns. It has a rolled vernation and a membranous ligule with jagged edges. It looks a little like creepting bentgrass, but it does not have a long membranous ligule that typifies bentgrass and has fine hairs around the collar. It forms a narrow spike-like panicle of seeds, with each seed having a fine awn (hair) at its tip (Figure 1).

It has been nearly impossible to control once it has become established in the lawn. It can be killed by nonselective herbicides, but it is also a good seed producer and it often returns from seed. It is a warm-season species and it looses its chlorophyll in the fall and takes on a bleached, straw-like appearance that makes it stand out in cool-season lawns. It is sometimes referred to as ‘wire grass’ in parts of the Midwest.

Tenacity (mesotrione), was released into the lawn care market in the spring of 2011. It had been available for a few years in the sports turf and golf markets. This material can selectively control nimblewill in Kentucky bluegrass turf. It is also labeled for the control of creeping bentgrass in Kentucky bluegrass and for the pre and postemergence control of crabgrass.

The pictures below are from the lawn of our "answer-line" person in the department, Richard Jauron. Richard gets a number of questions on nimblewill control and decided to do a test in his own lawn. These pictures are from the 5th of July, 2011. Richard will continue to update us on his experience with the material throughout the season. The material will turn susceptible weeds snow-white when it is first applied. It does take at least two applications for complete control of nimblewill, and may take more treatments. Remember too that nimblewill is a good seed producer. We will follow this through next season as well and not stop until control is complete.

STAY TUNED!

Figure 1. Seed head of nimblewill with "awns".

Initial effect of tenacity on nimblewill in Richard's lawn. The white color is a typical response to this herbicide. Richard will repeat apply two weeks after the first application.

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