Unusual September Weeds and Diseases in Iowa

Ryan Adams

9/24/2013

With last week’s abnormally warm September weather, several diseases and weeds were discovered around the state of Iowa. Brown patch thrived with night temperatures above 70F⁰ coupled with high humidity. Brown patch is caused by the fungal organism Rhizoctonia solani. Damage affects the leaf blade from the tip down and is usually noticed in grasses which receive high amounts of nitrogen fertilization. Symptoms are straw colored irregularly shaped foliar lesions with a brown boarder. R. Solani can attack most cool-season grasses, but is most commonly noticed on creeping bentgrass greens, tall fescue lawns and Kentucky bluegrass.

Symptoms on bentgrass putting greens appear as a copper/gray-colored “smoke rings” ranging from a few inches to several feet where mycelium can be seen. Figure 1 below was taken last week by Dan Strey at the ISU research station. Figure 2 is from University of Missouri Extension IPM: Identification and management of turfgrass disease - looking at leaf and sheath lesions of brown patch.  

Figure 1: Brown Patch at ISU research station

Figure 2: University of Missouri publication looking at tall fescue foliar syptoms of brown patch

There are many fungicides that provide brown patch control such as Daconil, Banner Maxx, Heritage, and several others. Cultural practices such as reducing nitrogen levels and preventing long periods of wet conditions can reduce disease pressure. With temperatures tapering off over the weekend, hopefully it will be the end to the high temperature summer diseases in Iowa.

Oddly enough, in the middle of September we have also seen crabgrass and goosegrass seedlings germinating at the ISU research farm. Normal crabgrass germination occurs in mid-April to mid-May depending on your location in the state. Crabgrass is easily identified with fine hairs on the leaves and sheaths as well as its distinctive “protruding fingers” seedheads. Crabgrass also has a rolled vernation, while goosegrass has a folder vernation. 

Goosegrass is often mistaken for crabgrass and some people incorrectly refer to it as “silver crabgrass” because if it’s silvery appearance of the lower sheaths.  Goosegrass generally germinates 2-3 weeks later than crabgrass in the spring. The seed stalks of goosegrass also appear somewhat like a zipper with two individual seeds protruding in two directions. In figure 3 and 4 below you will see the side by side comparison from the Scotts grass manual.

 

Figure 3 and 4: Goosegrass and Crabgrass comparison from Scotts grass manual

Goosegrass is very difficult to control, even with the use of preemergence herbicides. The best postemergence option is a nonselective herbicide such as glyphosate. Optimal crabgrass postemergence control is obtained when applied while the crabgrass is small and actively growing. The use of fenoxyprop, quinclorac, and dithiopyr are the best options.

WINDMILL GRASS (Chloris verticillata)

 Nick Christians
September 19, 2013
nchris@iastate.edu


It's that time of year again when I'm getting calls and receiving pictures of a very annoying weed in lawns.  The weed is Windmill grass (Chloris verticillata), a warm-season grass that has thrived in the hot and dry period of late summer.  The seedheads are just now reaching full maturity and it is readily visible in dormant Kentucky bluegrass lawns.

It produces a lot of seed on the windmill-like seed head.  These seedheads will break loose when the seed is mature and it will roll across the lawn on windy days like a tumble weed and disperse the seed on surrounding areas.  Next year there will be more of it.

It is relatively new in central Iowa and we are still trying to figure out how to deal with it.

Roundup will kill it non-selectively, but it is a great seed producer and it will come back.  Tenacity (mesotrione) is labeled for it, but it will require persistence and you can expect new plants from seed in the spring.

Here are a few pictures that will help in identifying it.

This is a drawing of it from the Scotts Manuals on grass identification.

Seedhead found in a cemetery in Ames, Iowa.

 I took the next 3 pictures this morning just outside of Nevada, Iowa, in a dormant lawn in a park area.  The seedheads reach a height of 6 to 8 inches in some of the patches.

BERMUDAGRASS ON IOWA STATE CAMPUS

Nick Christians
September 18, 2013

I have been doing plant walks on Iowa State Campus with students in the Hort 351 lab for 34 years before this fall.  I have never found bermudagrass on campus, with the exception of that which was planted on the steam tunnel a few years ago.  But outside of the very warm soil on the steam tunnel, our winters have been too cold for it to survive.  However, this fall, in my 35th year of doing this, there is bermudagrass that is not on the steam tunnel.  It is located in front of the genetics building.  Spence Nelson, president of the turf club, found it this morning.  The first picture is of the patch of bermuda and the second one is of a stolon that he brought in from the patch.  Notice that the bluegrass surrounding it is still dormant in mid September.  We went more that 70 days without significant rainfall.  Just this week, we had one half inch.  Hopefully we will get more tomorrow.  This shows how much better adapted warm-season grasses like bermuda are to drought.

There have also been several reports of bermudagrass in lawns and sports fields in central Iowa (see earlier posts on this subject).  While this is great for teaching, it can be a serious weed problem in our cool-season turf.  It will be interesting to see if it continues to survive our winters over the next few years.

10th Annual Wee One Foundation Golf Outing

Ryan Adams

9/17/2013

As the story is told, “In 1985, four friends traveled to Scotland on a golf trip. The caddies were making wagers as these golfers stood on the tee. One caddie declared, "My money's on the wee one!" The "wee one", Wayne Otto, CGCS, our dear friend and colleague, passed away October 21, 2004 losing his battle to cancer. Wayne dedicated his life to the betterment of the golf maintenance profession he loved and the individuals who shared his passion. Through the perseverance and hard work of several friends of Wayne, the group developed its mission of helping those in need. Founded on the principles of assisting golf course management professionals (or their dependents) who incur overwhelming expenses due to medical hardship without comprehensive insurance or adequate financial resources, the Foundation has evolved into a cause that goes way beyond its initial reason for existence.” 

Yesterday, one-hundred and sixty-two participants took aim at Pine Hills Country Club in Sheboygan, WI to support the Wee One Foundation. Of the 162 attendees, Jeff Wendel (Iowa Turfgrass Institute), Patrick Wynja (Jewell Golf & Country Club), Drew Blocker (Crow Valley Golf Club), and Ryan Adams (Iowa State University) fielded two teams representing the Iowa GCSA. The Iowa GCSA is a yearly platinum sponsor for the event. Overall, it was a great day filled with smiles, tacos, and a beautiful late summer day on the banks of Lake Michigan. 

Since 2004, the Wee One Foundation has grown to over 350 members in 17 states. Even more valuable than the distance covered, is the amount of lives affected. Over $600,000 has been raised for families across the Midwest. I would like to personally thank everyone who put their time and effort into making yesterday’s event a success. It was truly a great event, for a special cause. 

MANAGING WATER IN DROUGHT CONDITIONS

Nick Christians
Sept. 13, 2013
nchris@iastate.edu

Here is a post from John Temme, Superintendent of Wakonda Country Club in Des Moines.  It was originally sent to his membership.

John's contact information is:
 
John Temme
Superintendent
Wakonda Club
1400 Park Ave.
Des Moines, IA 50321-1846
United States
Phone: (515) 255-5898
Fax: (515) 698-9810
E-mail: johnt@wakondaclub.com

Managing Water in Drought Conditions Thank you for your patience and understanding while we manage the turf during the extreme heat.  Water management for golf course turf varies when you consider what soil and turf type is present in each area.  At Wakonda Club, my two assistants (Jim and Shawn) and I are constantly monitoring weather patterns, soil types, and turf needs to apply water when needed. We wanted to provide you with some interesting facts on how we create a beautiful golf course, even when mother nature is not cooperating. ·         Greens – Our new A1/A4 greens are very heat and moisture tolerant, meaning they hold up exceptionally well in dry/hot weather. ·         Tees – Our tees are built on a sand base so they drain really well; therefore, requiring more water than the fairways and greens. ·         Fairways – We have a nice stand of Penn Eagle II/Penn Links II bent grass with some Poa annua mixed in. “Poa” is a shallow rooted plant that cannot withstand high temperatures and no rain. So, to keep this plant alive during hot, dry conditions, we water more frequently resulting in softer fairways at times – especially in the valleys. Technology ·         This season we are monitoring turf moisture with the help of the TDR 300 moisture meter – this device gives us a volumetric moisture reading in the soil.   We use this data to set up the irrigation system each night. ·         The irrigation system is run by a series of computer programs  that control over 800 irrigation heads on the golf course.  Each head is set to run different, for example, the hills receive more water than the valleys.   This system is very sophisticated but not perfect.  ·         This year we have implemented the use of soil wetting agents on tees and fairways.  This product helps the soil absorb moisture more evenly and has helped us produce better playing conditions. ·          To date, we are using 60,000 gallons less water/ day compared to last year under similar environmental conditions. Thank You, John and Fiona #1 Fairway in 2012 #1 Fairway in 2013.