Wednesday, July 31, 2013


Nick Christians
July 31, 2013

Here is a news release from Iowa State on tomorrow's field day.

Iowa State University
College of Agriculture and Life Sciences

Editor's note:  This release, sent Wednesday, left out the field day's starting time. It is 8 a.m.


Nick Christians, Horticulture, (515) 294-0036,
Ed Adcock, Agriculture and Life Sciences Communications Service, (515) 294-2314,

Aug. 1 Field Day Brings Turfgrass Specialists to Iowa State University Research Station

AMES, Iowa — Turfgrass specialists who work with golf courses, athletic fields and lawn care services will meet at 8 a.m. Aug. 1 for an annual field day at the Iowa State University Horticulture Research Station.

Faculty and staff from Iowa State departments of horticulture, agronomy, entomology and natural resource ecology and management will present informational sessions along with speakers from the Iowa Department of Agriculture and Land Stewardship and Indian Hills Community College. Topics include pond management, pesticide application, weed management and turfgrass insect, weed and disease identification.

The field day includes a Pesticide Applicator Training session to meet requirements for applying pesticides. Suppliers of turfgrass products will exhibit at the field day.

Registration information is available at The Horticulture Research Station is located at 55519 170th St., Ames, which is three miles north of Ames on Highway 69, and east on 170th Street about 1.5 miles.

Iowa State sponsors the field day with the Iowa Turfgrass Institute, the Iowa Golf Course Superintendents Association, Iowa Sports Turf Managers Association and the Iowa Professional Lawn Care Association.


On the Web: This and all other Iowa State University College of Agriculture and Life Sciences news releases and related photos are available at

Monday, July 29, 2013


Nick Christians
July 29, 2013

I received the first picture from  Rob Elder of Omaha Organics.  It is a stolon of bermudagrass Cynodon dactylon.  As is the case in central Iowa, this is unusual for the Omaha area.  Not long ago, you would not have found this species in that area because it would die each winter due to the cold weather.  It is now surviving the winter.

How can you tell it is bermudagrass?  While the long stolon is a pretty good clue, there are other species with stolons, so you have to look close at its characteristics.  The first clue is vernation, as pictured below.  Vernation is the way in which new blades emerge from the sheath.  Bermuda is folded like the grass on the left, while Zoysiagrass is rolled like the grass on the right.  Creeping bentgrass can also form a stolon like the one above.

Bermudagrass and Zoysia have a hairy ligule like the one on the right in the picture below, whereas bentgrass has a membranous ligule like the one on the left.

Here are two actual pictures of the hairy ligule of bermudagrass.  If the grass that you are trying to identify has a membranous ligule, it will likely be a cool-season grass.  If it is a warm-season grass like bermuda or zoysia, it will have a ligule that is a fringe of hairs.

Thursday, July 25, 2013

Sclerotium rolfsii Spotted at the ISU Horticulture Research Station

          This spring, as you all know, brought large amounts of rainfall to central Iowa. This was a blessing for most including us the Horticulture Research Station. The water level in the pond returned to its maximum height, soil moisture reached great depths, and reduced the amount water needed to irrigate. The record breaking rainfalls also encouraged moss growth on one of our putting greens. Over the years, we have tried to encourage this growth to continue research on moss controls.

   A couple of weeks ago, I noticed spots on the green that appeared to look like dollar spot, however, the spots were only covering the moss and not the bentgrass. I decided to leave the area untreated to see if these spots would continue to spread or remain localized. Within a few short weeks, the disease spread like wildfire across the moss. A sample was taken to the Disease Diagnostic Clinic here at Iowa State University. The pathogen was identified as Sclerotium rolfsii.


            Sclerotium rolfsii is a fungal disease that has an extensive host range that targets over 500 species. It is very common in the tropics, subtropics, and other warm temperature regions. However, it is very rare to see the disease this far north. The pathogen rarely occurs when winter temperatures fall below 32˚F. The disease survives in the form of sclerotia. These sclerotia are easily spread by foot traffic and mowing equipment. Most of the research articles that I have read state that control is relatively difficult to achieve. We will continue to monitor the area and post any updates on the control.

Tuesday, July 23, 2013


Nick Christians
July 23, 2013

Dan Strey and myself spent last week in Beijing China for the 12th International Turfgrass Research conference.  It was an excellent meeting, with more than 300 people in attendance.  As you can see, we had a beautiful, clear day at the Great Wall.  

It was a little hazy for the  Forbidden City.

Iowa State was well represented with 6 papers that are listed below.  Full text of these will be up on the Turfgrass Information Service soon.  I can also send full text to anyone who would like them.

N.J. Dunlap, N.N. Boersma and N.E. Christians

Marcus A. Jones and Nick E. Christians

Core Aeration Programs and Sand Topdressing
Improve Creeping Bentgrass Fairways
Matthew T. Klingenberg, Deying Li, Nick E. Christians* and Christopher J. Blume

Influence of an amino acid complex on the growth of
Agrostis stolonifera L. cv. Penncross
Quincy D. Law*, Marcus A. Jones, Aaron J. Patton, and Nick E. Christians

Basic Cation Saturation Ratio Theory Applied to
Sand-Based Putting Greens
R.A. St. John* and N.E. Christians



A.H. Hoiberg and D.D. Minner

Wednesday, July 10, 2013


Nick Christians
July 10, 2013

These are pictures of Summer Patch on Kentucky bluegrass at the Horticulture Research Station.  It is caused by the fungi Magnaporthe poae.  It typically shows up in early summer, particularly in years like this that are very wet early followed by a quick drying period and hot temperatures.  This showed up over the 4th of July (right on time).

The blighted areas with a green center that are surrounded by a circle of dead grass are known as “frog-eyes” and are typical of a number of patch diseases.  It is believed that the organism begins as a saprophyte (organism that feeds on dead plant material) in the middle and moves outward in a circle without damaging living grass.  It only attacks living grass if conditions are right and it reaches a certain level of virulence. The patches here are 10 to 12 inches in diameter, which is common for this disease.

There are several systemic fungicides labeled for this disease, but the trick is to get them down before the symptoms develop.  Contact fungicides will not work.  To treat now would do no good and the symptoms will like last through the summer.  This is a disease for which good records are a must.  On this area, I would need to apply a systemic fungicide in late June next year before symptoms develop.  Core aeration in the fall and irrigation during the stress period of early summer can also help prevent its development.

Friday, July 5, 2013


Nick Christians
July 5, 2013

On June 26, I posted the two pictures below about what appeared to be a strange organism growing on urea pellets.  Several experts at Iowa State looked at the pictures and could not determine what the problem was.  Last week, we received a sample of the material.  To everyone's surprise, this was not an organism at all, but a formation of chemical crystals that appear to be biological but are in fact chemical in origin.  They are even green in color and look exactly like an organism.  We have no idea what conditions can lead to the formation of these crystals of this type on urea.  If anyone has any further insights, let me know.

Monday, July 1, 2013


Nick Christians
July 1, 2013

I received information on the first sightings of Japanese beetles for the 2013 season over the weekend.  Larry Ginger of American Lawn Care reported a sighting in Ames from  June 27.  Dr. Donald Lewis, the turf entomologist from Iowa State also reports a sighting from June 26.  I have not seen any yet myself, although I have been watching.  I am planning a trial on the control of this insect on Roses that I will not be able to begin for a few days.

Let me know if others of you are seeing them.  Send pictures if you have them.

Larry reports that he has had good luck controlling them on landscape plants with a combination of Bisect for quick knock-down and Zylam for 30 day control.  Any other information on control would also be useful.

 Here is one of my photos of an adult form a couple of years ago.  They are about one half inch in length.