Wednesday, April 23, 2014

When do I apply my Crabgrass Preventer?

A key to the successful control of annual grasses (such as crabgrass) in established turf is the correct application timing of preemergence herbicides. Preemergence herbicides should be applied by May 1st in central Iowa. Dr. Christians has noticed that this date does not vary much from year to year, after monitoring germination dates for the last 34 years.
In addition to timing: application uniformity, using recommended product rates, and the requirement of (1/2 inch) irrigation within 3-5 days of application can play a vital role in crabgrass control. 

Several products are available for effective annual grass emergence control. These products vary slightly in mode of action, length of control, specific weed efficacy, desired turfgrass seed inhibition, and early postemergence control. Benefin, benefin + trifluralin, bensulide, oxadiazon, siduron, pendimethalin, mesotrione, prodiamine, isoxaben, and dithiopyr are preemergence products available in the market today. 

Please note that some products are not labeled for certain turfgrass species. For example, oxadiazon is not recommended for use in fine fescue; however, oxadiazon provides   excellent goosegrass control in Kentucky bluegrass. Always read thoroughly and follow the label directions. Remember, the label is the law.

Dithiopyr and prodiamine have the longest window of effectiveness and can control weeds for up to 16 weeks. Dithiopyr and mesotrione offer early postemergence control when applications are made following weed emergence. Siduron and mesotrione have a unique property that allows herbicide application to seeded areas. Siduron selectively controls weedy annual grasses such as crabgrass, foxtail, and barnyardgrass, while allowing the desired turfgrasses to grow.  Mesotrione is only labeled for preemergent use on newly seeded Kentucky bluegrass lawns. All of the other preemergent herbicides kill the seeds of the cool-season grasses and cannot be used at the time of seeding.

Fertilizer-herbicide combinations are sold at most retail stores. This allows homeowners to combine the two operations into one application. A disadvantage of the combination is that the proper time for weed control often does not coincide with the optimum time to fertilize. Combinations with preemergence herbicides are generally effective in controlling annual grass weeds as long as applications are made at the appropriate time and recommended amount.

In addition to annual grassy weeds, a spring application of a preemergence herbicide will control annual broadleaf weeds, such as prostrate knotweed and spurge. A second application at a reduced rate may be necessary for season-long control. 

Paying attention to herbicide timing, application uniformity, product and rate, and ensuring (1/2 inch) irrigation within 3-5 days of application will help prevent annual grass (crabgrass) invasion. Below you will see two pictures of crabgrass in an early leaf-stages.

The last picture is a general guide of preemergence application dates via Quali-Pro's Prodiamine label:

Thursday, April 17, 2014


Nick Christians
April 17, 2014

It looks like the big winner (or loser depending on your perspective) this winter was perennial ryegrass (Lolium perenne).  We use this species in the Midwest on some golf course fairways and a large number of sports fields. It is also often included in lawn seed mixes.

Perennial ryegrass has good wear tolerance and germinates very quickly in spring and fall.  I find that I will get germination from perennial rye weeks early than I do from Kentucky bluegrass (Poa pratensis) in spring seedings.  It also matures quickly, and recovery from winter damage takes place much faster than from spring seedings of Kentucky bluegrass.  On golf course fairways and tees, we can get the playing surface back in a few weeks from rye seedings, whereas it can take months for Kentucky bluegrass to provide a complete cover from a spring seeding.  We generally seed the rye at 3 to 5 lbs/1000 ft2 in mid-April.  If you had damage on rye this spring, I would recommend seeding as soon as possible.  If you are planning to overseed Kentucky bluegrass, you will likely see little germination before mid-May and then recovery will be painfully slow unless you cover the area with tarps to speed the process.

We had one of the coldest winters in years in 2014, as Ryan and myself have mentioned in blogs over the past 3 weeks.  We have had a few contacts about loss of Poa annua on golf courses, although it does not appear to be very bad in most of Iowa.  Creeping bentgrass (Agrostis stolonifera) damage appears to be minor as of mid-April.   There is also a little damage on Kentucky bluegrass, although that will generally recover from rhizomes in years like this.  Perennial ryegrass is another matter.  We are just beginning to get contacts about rye damage.  The pictures below are form sports fields and golf courses in central Iowa.  This is further south than we normally see winter damage on this species, which makes me wonder how much damage we are seeing in northern Iowa and southern Minnesota. 

Perennial rye does not have a rhizome system like Kentucky bluegrass and generally requires overseeding in the spring when damage occurs.  The good news is, you can get it back much more quickly than other species (see the pictures from Vennker Golf Course on Iowa State University campus from 2008).

Let me know if you are seeing winter damage on your area and send me some pictures as well.  It will be interesting to watch recovery as the spring progresses.  

The first 4 pictures are from Jester Park golf course in Central Iowa.  These are mostly ryegrass fairways with a little Kentucky bluegrass mixed in.

The undamaged area in the left of this picture is Kentucky bluegrass.  The damaged area is perennial rye.

 These pictures were taken on a mostly perennial ryegras soccer field on ISU campus.  Notice the mole run in the first picture.  Thanks to Brent Cunningham for the pictures.

 This set of pictures is from John Newton, certified golf course superintendent at the university golf course.  It shows winter damage on his ryegrass fairways in 2008.  The area was seeded with 3 lbs rye per 1000 sq ft on April 10.  The second row of pictures show flood damage in May with recovery by the end of the summer.  John had a tough year in 2008.

Wednesday, April 16, 2014


Nick Christians
April 16, 2014

Here are some pictures from Tim Christians and Brian Thomson who are both superintendents in the Chicago suburb of Barrington.  The storm was last weekend.  The hail stones were the size of golf balls and larger and did much of the same damage that a golf ball would do.  They ended up having to fix thousands of holes in the same way they would fix a ball mark.

They also had quite a bit of damage to cars in the parking lots.

Tim reports that this hardly slowed the golfers down.  Right after the storm, the pro shop sold out of colored golf balls and the players just kept going.


Monday, April 14, 2014

Are My Greens Still Alive Update

The first section of this blog will highlight a quick update from Tim at Short Hills Country Club in East Moline, IL. I posted a few pictures of Tim’s greens and damage in a previous blog. The earlier pictures were from March 24th and the second set was taken a week later on April 1st. Tim covered his greens and was getting an 8-degree temperature increase on sunny days. The soil temperatures in the Moline/Davenport area have already risen to 58 degrees in the top 4 inches. This rest of Iowa is currently in the mid to high 40’s. Tim saw increased green tissue appearing over the last week. In the upcoming weeks, he is going to hit them with a shot of soluble nitrogen and a Florentine package. They are hopeful of a full recovery by mid-late May.  Below you will see a before and after picture of the same green.

Below you will find a chart looking at the low temperature hardiness of several turfgrass species produced by Beard (1973).

Low-temperature hardiness
Turfgrass species
Rough bluegrass

Creeping bentgrass
Kentucky bluegrass

Colonial bentgrass
Annual bluegrass

Tall fescue

Red fescue
Perennial ryegrass

As we progress down the list, we are seeing additional damage. In the last few days there has been extensive damage reported to perennial ryegrass stands in central Iowa. Prairie Ridge Sports Complex in Ankeny, IA and across Saylorville Lake in Granger, IA at Jester Park Golf Course is seeing widespread damage of perennial ryegrass fairways and soccer fields. Last week, I visited Elliott Josephson at Prairie Ridge and both of his perennial rye soccer fields have extensive damage. Digging down into the P-rye, there was some slimy green tissue at the soil level, but he has not seen much recovery over the last week. Elliot decided to take a proactive approach about two weeks ago and has already initiated reseeding the field. Supplementary seeding will take place this week. These two particular soccer fields receive high amounts of play and traffic throughout the year from mid-April to mid-late November. I believe the excessive traffic and wear has contributed to the winter damage.  

 Perennial Ryegrass Soccer Field at Prairie Ridge
High traffic and wear area on field above

In addition, last week Nick and I traveled to Jester Park (pictured below) to meet with Superintendent Bob Begey who is seeing extensive perennial rye fairway damage. More information and updates will be available this week. If you are seeing damage, please let us know.