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Wednesday, July 1, 2015

RED THREAD SHOWING UP AT RESEARCH STATION



Nick Christians
July 1, 2015

Red Thread is a turfgrass disease caused by the fungi (Laetisaria fuciformis).  It occurs on most major turf species, generally on areas that are somewhat deficient in nitrogen (N). 

We are seeing a lot of it this week on both Kentucky bluegrass and perennial ryegrass.  It has not shown up on tall fescue as of July 1.  The disease gets its name from “red threads” that appear near the tips of the leaf blades.  These threads are much larger than microscopic hypa(e) and are readily visible with the naked eye. The red threads are known technically as stromata or stroma. The disease may also express itself as a mycelial mass (group of hyphae) that appear as tufts of cottony-like material that appear over the surface over the turf.  The blighted areas are usually a few inches in diameter, about the size of a soft ball.  It can blight an entire turf area under the right conditions.

While we commonly see it on perennial ryegrass in most years, widespread outbreaks on bluegrass, such as we are seeing this year, are unusual.

Fertilizing the area with N can be an effective cultural practice to handle this disease.  There are also several fungicides labeled for it.  The disease usually runs its course on Kentucky bluegrass and the application of fungicides are generally not necessary.

The first picture is from Larry Ginger of American Lawn Care, who reported seeing red thread in early June.






This is a picture from the research station take today (July 1, 2015)


The next two pictures were taken at the research station in past years.


Thursday, June 25, 2015

FALSE JAPANESE BEETLE (Strigoderma arbicola) showing up in Iowa

NICK CHRISTIANS
JUNE 25, 2015
nchris@iastate.edu

Here is a post from Dr. Donald Lewis, entomologist at Iowa State University.  In recent weeks, we have both been contacted about Japanes beetles (Popillia japonica) showing up in central Iowa.  Don has found that these are actually False Japanese beetles (Strigoderma arbicola). We do get Japanese beetles here, although last year populations were low.




Here is Don's post.



From: Lewis, Donald R [ENT]
Pest identification is a keystone to IPM.  An example going on now is the emergence of False Japanese Beetles (FJB) in eastern and central Iowa.  As the name implies, false Japanese beetle (Strigoderma arbicola) is very similar in appearance to the true Japanese beetle.  The major difference is the coloration.  False Japanese beetles do not have the bright green and copper coloration of the Japanese beetle.  They are dark tan to brown though the thorax may appear metallic green on some specimens.  False Japanese beetles do not have the five white hair tufts that are prominent on each side of the abdomen of the Japanese beetle.   Here is a link to a close-up photo of FJB where these characteristics can be viewed. 

The BugGuide website uses the common name “sand chafer” which matches very well the locations where we must commonly see this beetle in fields, gardens and lawns.  However, the common name “false Japanese beetle” has been used in Iowa for at least the past 50 years!  The False Japanese Beetle is moderately common in the state but varies greatly from year to year.  Others are reporting more than usual this year.

Technical information about false Japanese beetle:  http://bugguide.net/node/view/44690

An old article about FJB:  http://www.ipm.iastate.edu/ipm/hortnews/1999/7-2-1999/fjapbeet.html  Note since 1999 the true Japanese beetle has expanded its range in Iowa to 63 counties (not the 5 listed in the chart).

Thanks.

Donald Lewis

Donald R. Lewis
Professor
Department of Entomology
Iowa State University
Ames IA 50011

Wednesday, June 17, 2015

WINDMILL GRASS REARS ITS UGLY HEAD.

Nick Christians
June 17, 2015
nchris@iastate.edu

 Here are a couple of pictures of Windmill grass (Choris verticillata) from Larry Ginger of American Lawn Care in Des Moines, Ia.  This warm-season grass is fairly new to Iowa, but I get more questions on it every year.  As it matures, it will form a large, open seedhead that looks a little like a windmill.  It spreads by stolons and by seed and increases every year in this area, particularly along city streets and on south facing slopes.  The seedhead will detach from the plant at maturity and roll over the turf like a tumble weed to spread its seed.  This is the main reason that it has spread so quickly. 




Roundup will kill it, but that will also kill the other lawn grasses.  Tenacity (mesotrione) is also labeled for it, but you will need to be persistent to completely remove it.

Search this blog for early articles on this species.

Here is a closeup of the seed head as it will appear in late summer.



Here is a comment from Doug Schryver of Sterling, IL o


Nick,

     I just wanted to comment on your post about Windmill Grass. One of my duties at the Park District in Sterling Illinois is Turf Management and I’ve read where the only herbicide that is recommended for Windmill Grass is Tenacity. I live in rural Whiteside County (northwest Illinois) and the soil in our neighborhood is very sandy and I’ve noticed a lot of Windmill Grass in the area. About three years ago most of our front yard was Windmill Grass and I decided to try to rid the yard of it. Each spring I usually would use a de-thatcher on the yard until I realized that it was actually just mixing the seed from the Windmill Grass into the soil and opening up the soil to the seed, so I no longer de-thatch. I used Tenacity on the yard in three sequential applications 7-10 days apart and had good luck controlling the weed. At that point our yard was very thin in that area so the rest of the season I would physically pull any Windmill Grass plants that I would see along with collecting any seed heads that would roll into the yard from a neighbor. That fall I overseeded the area with Barenbrug 50/50 RPR (Kentucky Blue/Regenerating Perennial Rye) at 7 #/m and I was able to establish a very thick carpet of turf. Now I mow at 3” height of cut, twice a week and I’m very diligent about pulling any kind of weed and collecting any seed heads when I see them and fertilizing on a regular schedule to keep a thick canopy of turf to prevent the Windmill Grass from gaining a foot hold. It was a lot of work for about a year but now I’m very happy with the result! Some of my neighbors have noticed and have asked how I got rid of that pesky weed.
                                Sincerely,
                                                Doug Schryver