BUFFALOGRASS ROUGH AT ISU GOLF COURSE

Nick Christians
July 16, 2014

On May 28, Dr. Zach Reicher of the University of Nebraska and John Newton, CGCS at the Iowa State University golf course (Veenker Memorial) began a test of buffalograss (Buchloe dactyloides) as a grass for roughs.  Buffalograss is a warm-season species and is generally not used in our region.  Our wet climate generally assures that competing weeds out-compete the buffalograss over time and it is more difficult to maintain than the standard Kentucky bluegrass.

The release of Tenacity (mesotrione) gives us a new tool to fight weeds in buffalograss and the test is designed to determine if buffalograss is a viable option in our climate, if we can keep competing weeds from becoming a problem.  Zach's recommendation on the rate of Teancity is as follows:

Tenacity:

PRE on new seedbeds:  8 oz/A X 2, second app is about 4 weeks after germ maybe earlier if needed. Nonionic surfactant (NIS) in the last app.

POST on new seedlings: 5.3 oz/A X 3, two week intervals. NIS in the last two apps, but probably not the first app just to maximize safety.

POST on established buffalograss: 5.3 oz/A X 3, two week intervals. NIS in all  apps.

The buffalograss was a turf-type variety called "Bowie" (Gr-742).  An area a little larger than an acre between two fairways was killed with Roundup (glphosate) in mid-May.  Three methods of establishment was used.  One third of the area was tilled and seeded at 2 pounds of burs per 1000 sq.ft. The same rate of seed was slice-seeded into another one third and the final area was core aerfied and seeded.  The areas were irrigated until the seed germinated.  Tenacity was applied the week of June 9 and again on June 20.  We will continue to monitor the area for the next couple of years and keep you posted as to how it is working.

John and Zach on the day of seeding, May 28, 2014

Tilled area in the background and slice-seeding in the foreground. 

 Areified area was seeded with a drop seeder.

The area flooded in late June and was underwater for two days.

This is the site on July 16 (this morning).  The grass survived the flood well, except for one low area in the tilled area.  It is coming in well and the Tenacity has worked well on most weeds.  There is some prostrate spurge and yellow nutsedge, but most other weeds were controlled. 

Dollar Spot and Black Cutworms

Over the last three to four weeks I have received pictures from Neric Smith at Indian Hills CC (seen below), and also noticed dollar spot on several creeping bentgrass golf course tees/fairways across the state. Dollar spot is caused by the fungal pathogen Sclerotinia homoeocarpa. Generally, dollar spot develops when dew persists on the plant for greater than 8 hours. It is less dependent on temperature, and can develop over a wide range of temperatures (55-80°F). Turf deficient in nitrogen is the most likely situation where signs of dollar spot will occur. The disease gets its name from the silver-dollar-sized blighted areas that appear on closely mown creeping bentgrass. In Kentucky bluegrass and higher cut turf, the blighted area is about the size of a softball. Upon further examination of the turf affected by this disease, you will see an hour-glass shaped lesion in the middle of the leaf blade. The lesion is tan in the middle, surrounded by brown to orange halos on each side.

Active dollar spot infections produce a cottony white mycelium mass that is often evident on the turf during the early morning hours, not to be confused with spider webs. When viewed under a microscope the mycelium will exhibit y-shaped branching and the presence of septum (crosswalls). Pythium also produces this cottony white mass of mycelium but does not contain septum.

There are many ways to control dollar spot. The most important management technique is to increase N fertility in situations where N is found to be deficient. In addition to adding nitrogen; moderating thatch, removing dew, and preventing drought stress will help prevent the occurrence of dollar spot. The risk with many site-specific inhibitors is the development of dollar spot resistance. To prevent fungicide resistance use a rotation of chemicals and avoid repetitive use.  

The two pictures below were taken by Neric at Indian Hills.

 Cutworms:

The black cutworm is the most widely distributed cutworm that attacks turf in the United States. Cutworms do not overwinter in Iowa, but are brought up by winds from the south. Once they are established in the spring, they can undergo several life cycles before dying out in the fall. The adult is a dark-colored moth that is often observed fluttering around lights in the summer months. 

Cutworms, as the ones seen below, are commonly found in open aerification holes on golf course greens. A close look at the surface will reveal a lot of feeding damage around the holes.  They are often empty because of the feeding of birds. Cutworms are surface feeders and can easily be controlled with insecticides, the most common of these being Sevin (Carbaryl). While the larvae mainly emerge at night to feed, some may be seen on the putting surface during the day time, as was the case with the pictures below that was seen at Cedar Pointe in Boone a few weeks ago. 

 

 

 

NEMATODES ON BENTGRASS IN IOWA

Nick Christians

nchris@iastate.edu

June 30, 2014

Ryan Adams

rsadams@iastate.edu

Nematodes on turf is a problem that we usually don’t worry about in Iowa.  This is generally considered to be due to our cold winters that keep the population of this pest in check.  That’s why it is such a surprise to find them in numbers sufficient to cause damage after one of the coldest winters in years.

A few weeks ago, Ryan looked at some damage on Penncross creeping bentgrass (Agrostis stolonifera) greens at Westwood municipal golf course in Newton, Ia.  The symptoms looked like the patch disease Take All, caused by the fungi (Gaeumannomyces graminis).  Further tests at the Iowa State University Plant and Insect Diagnostic Clinic showed high numbers of lance (146 nematodes/100 cubic centifmeters cc) and stunt(144/ nematodes/100 cc) and some runner hyphae in the roots of the Gaeumannomyces.  It appeared that the nematodes may have weakened the turf and allowed the fungi to infest the plants, although we don’t know that for sure.

When symptoms of Take All Patch showed up on one of our research greens at Iowa State last week, we submitted samples to the Plant and Insect Diagnostic Clinic.  We didn’t expect nematodes because the damage is so rare here, but it turned out that we had 762 ring nematodes/100 cc and again this was found in association with Gaeumannomyces runner hyphae in the roots.  This is a sand-based green established with A-4 creeping bentgrass.  The damage appeared during an extremely wet period when the sand was nearly saturated.

A check of the internet for threshold levels of these nematodes shows a lot of variation around the country.  However, the specialists at the Clinic, feels that these levels are high enough to cause damage to creeping bentgrass in Iowa.

We plan to follow up with a field study on the area that will include both nematode and Take All control products in separate plots and in combinations.  We will keep you posted over the summer on what is happening.

If any of you suspect that you have this problem, let us know and submit a sample to the Clinic.  Their web site is http://www.ent.iastate.edu/pidc/.

Symptoms on green at Westwood municipal golf.

Ring nematode under microscope at the Plant and Insect Diagnostic Clinic.

Ring nematodes in the samples that we submitted to the lab.

 

SPORTS TURF PAINT PROJECT AT IOWA STATE-2014

Nick Christians
June 6, 2014
nchris@iastate.edu

Josh Lenz
jel007@iastate.edu

Josh Lenz is a new graduate student who is working on a masters of horticulture at Iowa State University.  He is doing the non-thesis option and will complete a creative component.  He works full time with the athletic department.

Josh will be looking at chemical and physical changes in the soil of sand-based sports fields subjected to repeated painting.

His treatments include:

1. Untreated control
2. Aerosol paint
3.  Acrylic paint 1:1 with water
4. Acrylic paint 2:1 with water (two part water:1 part paint)
5. Acrylic paint 4:1 with water

He will be painting the plots weekly through the season.  His measurements will include cation exchange capacity, nutrient holding capacity, water infiltration rates, bulk density and a variety of other physical soil parameters.  The study will go on for two years.