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Grass Can Be Green: Be An Advocate of Our Industry

April 28, 2010

It’s been awhile since I have posted to the blog. The hiatus is partially due to countless hours of preparation for my preliminary exam which was last week. A preliminary exam is a required step on the way to obtaining a PhD and might be best described as an exercise in poise, patience, and humility while demonstrating your ability to think on your feet. As part of my preliminary exam I was presented with an opinion article that recently appeared in the New York Times.

Here are some excerpts from the article which was titled “The Dandelion King.”

….The unkept look of my lawn is just a byproduct of a conclusion I reached a few years ago: the war on weeds, though not unwinnable, isn’t winnable at a morally acceptable cost.

….I soon learned that the carpets of green in suburbia are the product of assiduously applied chemicals. “Pre-emergent” herbicides are laid down more than once in the spring (mixed in with the fertilizer) to sabotage the germination of crabgrass, dandelions and other undesirables. If this fails, post-emergents may be applied en masse. And as the summer wears on, local pockets of resistance can be wiped out with a spray canister of poison.

….releasing dubious chemicals into the environment — is the inevitable result of using them on your lawn; you can’t negate this negative externality without rewriting the laws of nature.

….But for me, the practical way to have an eco-friendly lawn is to have a weedy lawn.

The remainder of the article is littered with further inaccuracies and embellishments that mislead the reader and paint a negative picture of turfgrass (the full article can be read at by clicking here).

I was asked, as a member and advocate of the turfgrass industry, to provide a rebuttal to this article as part of my preliminary exam. I believe articles of this nature reinforce the notion of the importance that each and every one of us does our part to educate our customers and the public about the benefits of properly managed turfgrass. Here are some facts about the benefits of turfgrass to the environment based upon published scientific literature. Equip yourself with this knowledge so you can provide an insightful answer next time you are challenged about the benefits of turfgrass. A comprehensive report detailing turfgrasses and their benefit to humans and the environment can be found here.

Environmental Benefits of Turfgrass

• Turfgrass provides a dense groundcover which protects the soil from water and wind erosion. Doubling the amount of turfgrass shoots in a lawn (32 to 64/sq.inch) reduced the amount of runoff by two thirds (Easton Z.M., and A.M. Petrovic. 2004. Fertilizer source effect on ground and surface water quality in drainage from turfgrass. J Environ Qual 33: 645-656)

• The dense canopy of well-maintained turfgrass coupled with its extensive, fibrous root system results in more water infiltrating through the soil profile. This enhanced infiltration increases groundwater recharge and reduces nutrient loss in runoff. Weedy-low quality lawns had three times more nitrogen runoff than a dense-treated lawn and no more phosphorus runoff (Easton, Z.M. 2005. Ph.D. thesis, Cornell Univ.)

• The turf-soil ecosystem supports a diverse population of soil microorganisms. These organisms are very efficient at degrading and trapping many of organic chemicals contained in runoff and sediment that occurs from impervious surfaces. Thin, weedy lawns leached 1-2 % of a herbicide compared to no leaching from a dense lawn (Easton, Zachary M., A. Martin Petrovic, Donald J. Lisk and Inga-Mai Larsson-Kovach. 2005. Hillslope Position Effect on Nutrient and Pesticide Runoff from Turfgrass. Intern. Turfgrass Soc. Res. J. 10:121-129).

• Turfgrass removes carbon dioxide from the atmosphere and replaces it with oxygen. This exchange of gasses allows turfgrass to act as a net sink for the sequestration of C02. Well-managed turfgrass receiving inputs can sequester larger amounts of carbon dioxide compared to lawns receiving no inputs (Zirkle, Gina Nicole. 2009. 2009 International Annual Meetings: [Abstracts][ASA-CSSA-SSSA]. p. [52288]).

Marcus Jones
Graduate Research Assistant


Diseases Running Wild (Leaf Spot, Rust and Summer Patch)

July 13, 2015

As the wet rainy summer continues, disease pressure continues to be high. As noted in a May 15th blog post, dollar spot has been extremely active this year. Leaf Spot has also been lingering across the state for 2 months. Leaf spot is an ascomycete fungi caused by Bipolaris spp. and/or Dreschslera spp. A majority of the damage recorded to this point has been on Kentucky bluegrass lawns, athletic fields and golf course rough, but symptoms on bentgrass fairways/greens have also been seen. Please refer to earlier posts for symptoms, pictures, and control options. 

In addition to the leaf spot calls, I have received several regarding Rust (Puccinia spp.). I first noticed rust at a Kentucky bluegrass sod field in the Des Moines metro about two weeks ago. It usually begins to show up about the first of August – mid September, however, in the last two years rust has showed up in early to mid-July. While several fungicides control rust, I usually do not recommend chemical treatment unless it is on high-maintenance areas. Furthermore, rust is usually a sign of relatively low nitrogen, and the addition of nitrogen and regular mowing will help in the removal of the disease. The yellow to orange flecks on the leaves and stems can be used to easily identify rust. As the disease progresses, orange and cinnamon colored blisters and pustules form. Clouds of spores can turn your shoes orange (as seen below in the pictures from Larry Ginger) when walking through perennial ryegrass or Kentucky bluegrass heavily infested with rust. 

Figure 1: Picture courtesy of Larry Ginger showing a close-up of rust on perennial ryegrass

Figure 2: Additional picture from Larry Ginger showing rust on shoes

Figure 3: The brown colored area on the left side is experimental plots that will be highlighted in future blog. A little tough to see, but the entire top portion is rust on Kentucky bluegrass along with small spots in the forefront.

As mentioned in the previous post by Nick Christians, summer patch (SP) reports are also coming in. A majority of the SP damage occurs between June and September on Kentucky bluegrass/annual bluegrass.  It is known as one of the “frog-eyed” diseases.  In mixed stands of grass, the symptom patter is more irregular. The best way to identify SP is by the sparse, dark colored runner hyphae on the outer surface of the roots. The infected roots are unable to supply adequate water to the turf causing the appearance of moisture stress.

Furthermore, SP survives winter as mycelium, and begins colonizing roots between 68-90oF. The fungi spread along roots and rhizomes from plant to plant. Summer patch damage is often large because it can spread long distances through aerification and infected sod. Often recovery is slow, since new roots are inhibited by high soil temperatures. Hot, wet weather, compaction, high pH soils, low mowing heights, south facing slopes, and the use of soluble fertilizers increase the risk of SP. Summer patch is most severe in 2-5 year old turf established from sod.  Severity can also increase when “muck soil sod” is placed on native Iowa soil.

Several curative and preventative fungicides are labeled for control. Applications need to begin early in the spring, when soil temperatures reach approximately 64 oF. Repeat application 2-3 times in 21-28 day intervals through mid-August. Once symptoms of SP appear, it is often too late for fungicides. Curative fungicides have proven to be inconsistent and cultural controls are the most effective option. Summer patch research has observed the best control using combination products containing DMI’s and strobilurins. DisarmTM, HeadwayTM, and ArmadaTM are a few of the chemical trade names that fall into this category. Other products such as fluxapyroxad, propiconazole, myclobutanil, thiophanate-methyl, trifloxystrobin, and triadimefon are labeled for summer patch control. 

When summer patch symptoms appear, it is most cost effective to control culturally. Foliar spoon-feed applications of ammonium sulfate at 0.1 -0.3lbs./N/1000 sq. ft. can briefly reduce severity. If foliar feeding is not an option, use slow release products rather than high rate applications of soluble nitrogen fertilizers. An annual spring application of magnesium sulfate may also reduce summer patch issues. 

In addition, raising the mowing height during high stress periods will reduce disease pressure. It is prevalent in compacted soils, so improving internal drainage through core aeration, and deep-tine aeration will help. If summer patch is an annual problem, consider overseeding resistant varieties. If battling summer patch exclusively Barvette, Nuglade, Midnight, Impact, and Sky are just a few of the Kentucky bluegrass varieties less susceptible.  Additional pictures from Doug Watt at West Marshall High School can be found below. 

Figure 4: Summer Patch pictures courtesy of Doug Watt


Isaac Mertz

Isaac Mertz is a graduate research assistant working on a Ph.D. degree at Iowa State University.
Graduate Research Assistant
Area of Expertise: 

Ground Ivy Control

August 11, 2016


                The objectives of this experiment were to 1) evaluate 3 different herbicides for their ability to control creeping charlie/ground ivy and 2) determine whether that ability could be improved through tank mixing with an additional herbicide from a different chemical class labeled for ground ivy control.

Materials and Methods:

                Ground ivy (Glechoma hederacea) samples taken from a residential landscape were transplanted into standard 5” diameter pots in a greenhouse and allowed to reestablish for seven days before being treated. The 5” diameter pots were filled with a standard potting soil mix which provided the plants with an optimal growing environment.

                Treatments (table 1) included an untreated control, triclopyr, tenacity, pylex, triclopyr + tenacity, and triclopyr + pylex. Treatments were applied foliarly using a hand-sprayer. Plants were irrigated prior to treatment, with all additional irrigation being withheld until 24-hours post treatment.






Untreated Control




1 fl. Oz./Gal./200 ft2



4.93 mL/2 Gal./1000 ft2



1 mL/Gal./1000 ft2


Triclopyr + Tenacity       

1 fl. Oz./Gal. + 2.47 mL/Gal.


Triclopyr + Pylex

1 fl. Oz./Gal. + 0.7 mL/Gal.

                                                                                  Table 1. Treatment and Rate Information

Non-treated Ground Ivy
Image 1: Non-treated Ground Ivy

Ground Ivy 10 days after treatment with Triclopyr

Image 2: Ground Ivy 10 days after Triclopyr only treatment

Ground Ivy 10 days after treatment with Tenacity

Image 3: Ground Ivy 10 days after treatment with Tenacity

Ground Ivy 10 days after treatment with Pylex

Image 4: Ground Ivy 10 days after treatment with Pylex

Ground Ivy 10 days after being treated with both Triclopyr and Tenacity

Image 5: Ground Ivy 10 days after being treated with both Triclopyr and Tenacity

Ground Ivy 10 days after treatment with Triclopyr and Pylex

Image 6: Ground Ivy 10 days after treatment with Triclopyr and Pylex


                When looking at the above images, it is easy to see the effect these chemicals have on the plant. Tenacity and pylex (trt’s 3 & 4) are both class 27 herbicides (pigment inhibitors). These chemicals are known for their ability to inhibit chlorophyll production, resulting in a bleached/white appearance on the leaves. It is important to note however, that the bleached appearance just means that the plant is affected by the chemical, and does not always guarantee control. In contrast to this, triclopyr, a class 4 herbicide, is known for its plant growth regulating activity. This is evident in the 10-d post treatment photo for treatment 2 above.

                According to the label for both pylex and tenacity, these chemicals can be tank mixed with an additional broadleaf herbicide, such as triclopyr. That was the driving force for this experiment. When reading the label however, it is unclear whether this tank mixture will increase in its effectiveness in controlling hard to kill weeds such as ground ivy. What is clear when reading the label, is that when applied in a mixture, the effect of class 27 herbicides on plants can be altered in the form of less bleaching occurring.

                This effect is evident in the pictures above, where the samples in images 3 and 4 showing signs of complete leaf bleaching (whole leaves turning white), whereas the samples in images 5 and 6 still show signs of bleaching, but a consistent pale green color still remains.

                Depending on who you talk to, the bleaching of plant leaves as a result of application may or may not be a favorable trait. To some, it is viewed as an indicator of progression, and that the chemical is working. Others may view it as a side-effect that could be deemed esthetically unpleasing. For those that fall into this category, tank mixing with an additional broadleaf herbicide may be a way to remedy this.

                While it is hard to say at this point in time, it does appear that the triclopyr addition to the tank mixtures is beneficial. While there is less bleaching occurring on an individual leaf basis, a larger number/bigger surface area of the treatment 5 & 6 pots appear to be affected compared to the treatment 3 & 4 pots, respectively. I will continue to let these samples persist in the greenhouse, and hopefully we will have a more definite answer down the road.






Construction Of Sports Turf Research Area At Iowa State

June 15, 2015

Here is a blog from Dan Strey, research associate at the turf research site.  It is about the new construction that he is doing at the Hort Research Station.  This will be part of the turf field day on July 23, 2015.

ISU Expanding Sports Turf Research
June 15, 2015
Dan Strey

Just over a couple of weeks ago, we began construction of a new three acre site that will be used for future sports turf research. The area will be divided into three different plots. The first being a native soil field. Topsoil from the existing site was stripped and stockpiled prior to reshaping. Once the clay subgrade was moved and leveled, ten to twelve inches of topsoil was then placed on top. The second plot will evaluate sand topdressing over existing native soil fields. The construction process will be similar to that of the native soil field. Once the area is seeded, topdressing will begin to take place. Lastly, the third plot will have a four inch sand cap. The subgrade will contain a minimum of four inches below the sand cap. The three plots were designed to represent the major types of fields being used and constructed in the state of Iowa as well as the Midwest.

The rough grade is nearing completion. We spent the last two weeks moving over 6,000 cubic yards of soil. We expect to begin the irrigation work within the next week or two. The system includes 72 heads, 24 electric valves, 8 isolation valves, 12 quick couplers, 3 miles of wire and 1.25 miles of pipe. Once complete, we will move on to the drainage system.

Last week the Iowa State News Service published a press release regarding the construction project. They included a video from the site. The link to the release is

 The Ames Tribune also ran a story on this last week, here is the link

Planning for the project started last fall where we identified the location, plans were constructed, and  sought out donations to help fund the project. We had an overwhelming response from the turf, irrigation, and construction industries. By early spring, the project was 100% funded. Here is a list of our sponsors and donors.


Hunter Industries

Cresline Pipe

Nibco Valves

Regency Wire

John Deere Landscapes

Rainbird Irrigation

Ziegler Caterpillar

Trimble GPS

Iowa Turfgrass Institute

Iowa Sports Turf Managers Assoc.

United Seeds

Bush Sports Turf

Lasco Fittings, Inc.

Harco Fittings

MTI Distributing

ISU Department of Horticulture


Thank you to everyone who has helped make this project happen!

Dan Strey


 Here are some pictures from the construction process.  As of June 15, the subgrade has been completed and the top soil placed. 



Jack Trice Preparations

September 2, 2016

Jack Trice is ready for the first game of the season, but getting to that point takes some time and hard work. I recently visited with Tim Van Loo Manager of Athletic Turf and Grounds for Iowa State University on what it takes to get Jack Trice ready. This year marks the 20th season since natural grass returned to Jack Trice Stadium. While much of the work is done during the summer, all of the painting is done just a day or two before the game. The grounds crew will mow the football field four times the week of the game, and they will always mow the same direction to make the light and dark stripes of the Kentucky bluegrass stand out. After a final mowing on Friday, the painting began.
Jack Trice Stadium before this week's painting.
This year the field was painted last week for the Victory Day, so some of the logos are still barely visible.

Three colors are used on the playing surface at Jack Trice Stadium: white, cardinal and gold.  The white is applied first with the white lines of the field painted first then the numbers and hash marks.
Hash marks being painted on the football field at Jack Trice Stadium
Care must be taken to not have paint drip when moving stencils.

Then the logos are painted and the end zones, sometimes the crew is large enough to paint several area's at once.Tim is assisted by 8 Iowa State Horticulture students focusing on turfgrass management and one Graduate Student in Horticulture with a focus on turfgrass management.
ISU Horticulture students studying turfgrass management help paint the football field.
ISU Horticulture students studying turfgrass management help paint the football field.

The center logo on the field spans from one 42 yardline to the other 42 yardline.

The red is painted first in the logos then the yellow.
ISU Horticulture Turfgrass Graduate Student Colton Metzger paints the midfield logo. 

It will take this crew 55 man hours to mix the paint, paint the field, and clean up the painters.  They will use 50 gallons of white paint, 40 gallons of gold, and 40 gallons of cardinal paint. On game day the crew will arrive 6 hours ahead of kickoff to mow the field, put out sideline tarps, and help with any other project that may need to be done in the stadium.
Number stencils are placed every 10 yards and painted white.
Tim Van Loo, Manager of Athletic Turf and Grounds for ISU, painting numbers for tomorrow's first game of the year.

Finishing touches on the numbers used on Jack Trice Stadium.

On a typical game day Tim estimates that around 600 to 700 people are on the field. After the game the crew will take screwdrivers and lift divots on the playing surface, similar to how a ball mark is fixed on a putting green, and the field will have the debris blown off of it. This process takes about two hours, allowing the crew to leave after Saturday's game around midnight.  

ISU Horticulture students focusing on turfgrass management help care for Jack Trice Stadium.
ISU Horticulture Students learn turfgrass management skills while helping take care of Jack Trice Stadium.


Go Cyclones!!




Summer Turf Diseases on Home Lawns

September 11, 2016

This past summer has been an exceptional year for diseases on turfgrass, and home lawns weren’t immune to these diseases either. Dr. Christian’s has mentioned several times this summer that this summer was the worst Brown Patch in Iowa he has seen in 30+ years. Summer temperatures often in the 80’s and lows in the upper 60’s with high humidity and rainfall made the conditions perfect for these summer diseases. The good news is that the temperatures seem to have cooled and repairs can be made to yards.

With the warm temperatures, ample rainfall, and high humidity this past summer, Iowa lawn’s endured prolonged periods of perfect weather conditions for brown patch (Rhizoctonia solani). This disease was noticed in Iowa from June on into September. It is often noticed as circular patches from a few inches to several feet.

Brown patch at the ISU Horticulture Research Station
Brown patch on creeping bentgrass putting greens at the Iowa State Horticulture Research Station.

The area in the patch can become killed and create a sunken patch, often though this disease will not completely kill the turf, but rather just thin those spots, which can recover with proper care after the weather conditions change. Brown patch lesions on leaves are easy to identify and are irregular tan or light brown in color with the edges of the lesions being a dark brown in color.

Brown patch lesions on turfgrass leaves
A close picture of brown patch lesions on turfgrass leaves.

Another problematic disease this summer was summer patch (Magnaporthe poae) which happens predominantly on Kentucky bluegrass and commonly occurs when temperatures are above 82. It is caused by a fungus that colonizes the roots. These patches often appear suddenly as small yellow patches, since the roots are affected, adding water will not help the declining turf health. As the grass dies it will turn a straw color. These patches often have areas inside of the patch that are not affected and seem healthy. Symptoms of summer patch will not be noticeable when the weather cools. Promoting healthy roots will help to minimize the impact of summer patch by regular aeration in the fall, mowing at proper mowing heights, and improving drainage in the yard.   

Disease on turfgrass lawn

If these diseases injured your turfgrass the fall is a great time to recover from them, as healthy turfgrass is the best way to combat weeds and disease next year. Make sure your yard is fertilized this fall, aeration each fall to improve gas exchanges to the roots and improve drainage making them healthier can help, follow proper mowing heights for the turfgrass species that are present in the yard, and overseed with more grass seed if large areas of dead turf exist.
Aerators can help improve drainage and promote healthy turf.
Aerators can help improve drainage and promote healthy turf.

One final note, several calls and emails this week have been related to people mistaking disease damage for chemical damage. Remember that typically disease damage will be patchy, while chemical damage would be a complete grass kill or in straight lines.  

Below are a couple pictures of disease damage on lawns from the Ames area:

Summer disease damage to a lawn in Ames


Turfgrass diseases can become a large problem is conditions exist for a long time.


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