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K-State Turfgrass

Month: August 2015

Reports of fall armyworms are coming in!

(By Jared Hoyle; KSU Turfgrass Research and Extension)

I have just received my first report of Fall Armyworms this year.  Last year we experienced a couple areas that had some damage but wasn’t very wide spread.  So to keep us prepared the link below goes to information about armyworm control that I put together last year.

http://blogs.k-state.edu/turf/fall-armyworm-has-been-sighted/

http://blogs.k-state.edu/turf/alert-more-sightings-of-fall-army-worms/

Keep a look out for fall armyworms.  A couple of reports have been around the Derby, KS area and have already caused some damage to tall fescue turf. These armyworms were already 1 to 1.5″ long.

Keep an eye out!

Power Raking or Core Aeration? That is the question!

(By Ward Upham and Jared Hoyle; KSU Research and Extension)

September is the optimum time to power rake or core-aerate tall fescue and Kentucky bluegrass lawns. These grasses should be coming out of their summer doldrums and beginning to grow more vigorously. This is a good time to consider what we are trying to accomplish with these practices.

IMG_1534   Power raking is primarily a thatch control operation. It can be excessively damaging to the turf if not done carefully. For lawns with one-half inch of thatch or less, I don’t recommend power raking but rather core aeration. For those who are unsure what thatch is, it is a springy layer of light-brown organic matter that resembles peat moss and is located above the soil but below the grass foliage. Power raking pulls up an incredible amount of material that then must be dealt with by composting or discarding.

Core-aeration is a much better practice for most lawns. By removing cores of soil, core-aeration relieves compaction, hastens thatch decomposition, and improves water, nutrient, and oxygen movement into the soil profile. This operation should be performed when the soil is just moist enough so that it crumbles easily when worked between the fingers. Enough passes should be made so that the holes are spaced about 2 to 3 inches apart. Ideally, the holes should penetrate 2.5 to 3 inches deep. The cores can be left on the lawn to decompose naturally (a process that usually takes two or three weeks, depending on soil-type), or they can be broken up with a power rake set just low enough to nick the cores, and then dragged with a section of chain-link fence or a steel doormat. The intermingling of soil and thatch is beneficial to the lawn.

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

For Seeding Success, Pay Attention to “Other Crop” on the Seed Label

(By Ward Upham and Jared Hoyle; KSU Research and Extension)

Fall planting time is close at hand, so it’s time to talk about grass seed. Many people have the idea that all grass seed is basically the same. Big mistake! Choosing quality seed is one of the most important steps in successfully planting or overseeding your lawn. If you don’t know what to look for, you may be introducing unwanted intruders into that new stand. In particular, we are concerned with seed contaminated with orchardgrass and/or rough bluegrass (also known by its Latin name, Poa trivialis, or Poa triv for short). These are both perennial grassy weeds that cannot be selectively controlled once they are in a lawn.

IMG_0661   Orchardgrass is a problem because it is faster growing and lighter green than our turfgrasses. It is a bunch grass and so doesn’t spread, but infested areas are still unsightly due to small tufts of this species pockmarking the lawn.

Rough bluegrass is fine-textured and forms circular patches in the lawn.  It blends in fairly well until summertime heat causes it to turn brown rapidly. If the rough bluegrass would just die in the heat, it would only be a temporary problem. Unfortunately, it usually just goes dormant, turning green again with cooler temperatures and rain.

Buying quality seed starts with knowing how to decipher the seed label. One of the most important things to look for is listed as “% other crop.” “Other crop” refers to any species that is intentionally grown for some purpose. That would include turfgrasses (those species other than the one you are buying) and pasture grasses. Orchardgrass and rough bluegrass both are listed as “other crop” seed. Seed labels are required by law to show the percentage (by weight) of “other crop” in the bag, but unless a species constitutes 5% or more, the label doesn’t have to list each species by name.

How much “other crop” is too much? That’s a difficult question to answer, but the tolerance is very low. It depends on what the “other crop” actually is, and the quality expectations of the buyer. In practice, “other crop” may refer to something relatively harmless, like a small amount of perennial ryegrass in a bag of tall fescue, or it may refer to something bad, like rough bluegrass or orchardgrass. The homeowner really has no easy way of knowing what the “other crop” is, although there are some hints. If it is something bad, less than ½ of 1% can ruin a bag of seed. Obviously, if your expectations are high for the area you are planting, you would want the “other crop” to be as close to zero as possible. Good quality seed will often have 0.01% “other crop” or less.

Also, Check your rules for selecting the right seed for you – http://blogs.k-state.edu/turf/the-art-of-knowing-your-seed-label/

***Mention of trade names or commercial products in this article is solely for identification purposes and does not imply recommendation or endorsement, nor is criticism implied of similar products not mentioned by Kansas State University.***

Don’t forget to follow me on twitter @KSUTurf.

Also, visit our facebook page www.facebook.com/KSUTurf

 

Grey Leaf Spot

(By Jared Hoyle; KSU Turfgrass Research and Extension)

Hope you haven’t seen it this year and won’t see it but I have talked to some people and have already heard of a couple occurrences of gray leaf spot.

So instead of typing out all the information about grey leaf spot I will send you to a great resource that has tons of information about great leaf spot.

Check it out here – http://www.turffiles.ncsu.edu/diseases/gray-leaf-spot

Also check on page 13 for more control options for grey leaf spot in this publication – http://www2.ca.uky.edu/agc/pubs/ppa/ppa1/ppa1.pdf

 

 

 

Top Quality Tall Fescue Varieties for Kansas

(By Jared Hoyle; KSU Turfgrass Research and Extension)

tall fescueKansas State University and The National Turfgrass Evaluation Program (NTEP) work together to determine the best adapted tall fescue cultivars for Kansas. This standardized program coordinates uniform evaluation research trials from turfgrass selections across the United States and Canada. These research trials are conducted over many years and data is recorded throughout the duration of the experiment. Recorded data includes turfgrass quality, color, texture, density, green-up, establishment, drought tolerance, winter injury and disease/insect damage. To find out more information about NTEP go to – http://www.ntep.org.

The tall fescue varieties listed below were the top preforming varieties from 2013 and 2014 data in the 2012 National Tall Fescue Test located in Wichita, KS. The list contains only varieties that are commercially available in 2015. Varieties were selected according to the mean quality ratings from April to October. Tall fescue varieties listed were not statistically different from the top performer. Turfgrass quality ratings take into account the aesthetic and functional aspects of the turf. Turfgrass quality is based on a combination of color, density, uniformity, texture, and disease or environmental stress. Other tall fescue varieties in the evaluation trial may preform well in Kansas. Any tall fescue variety with a rating of 6 or above is considered acceptable. For the complete list of tall fescue varieties and performance data go to – http://www.ntep.org.

2013 Data

  • Hot Rod
  • GTO
  • Rhambler 2 SRP
  • Michelangelo
  • 4th Millennium
  • Faith
  • Firebird 2
  • Grande 3
  • Fayette
  • Thor
  • Maestro
  • Temple
  • Fesnova
  • Hemi
  • Black Tail
  • Avenger II
  • Firewall
  • Technique
  • Rowdy
  • Reflection
  • Falcon V
  • Foxhound
  • Leonardo
  • Rockwell
  • Firecracker SLS
  • Dynamite LS
  • Titanium 2LS
  • Terrano
  • Raptor III
  • BIZEM
  • Bullseye
  • Diablo
  • Screamer LS
  • Saltillo
  • Caesar
  • Hover
  • Catalyst
  • Kingdom
  • Frontline

2014 Data

  • Thor
  • Technique
  • Temple
  • Falcon V
  • Michelangelo
  • Rockwell
  • Black Tail
  • Avenger II
  • Terrano
  • Reflection
  • Firebird 2
  • GTO
  • Meridian
  • Rowdy
  • Maestro
  • BIZEM
  • Screamer LS
  • Titanium 2LS
  • 4th Millennium
  • Traverse 2 SRP
  • Grande 3
  • Leonardo
  • Firecracker SLS
  • Dynamite LS
  • Rhambler 2 SRP
  • Saltillo
  • Catalyst
  • Kingdom
  • Hot Rod
  • Swagger
  • Raptor III

Names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products.

Root decline, it ain’t benign

(Megan Kennelly)

In the past 2 weeks we have posted a series of articles related to root health and rootzone management. I’m following up here with a few more photos (click to zoom any of the photos below).

Most of the samples have shown layering, thatch, and a build-up of organic matter.  These can reduce drainage, and roots suffer from lack of oxygen. Furthermore, wet soils hold heat, so the turf gets a double whammy of wet + hot. Steam-cooked turf is not happy turf. I’ve seen some very unhappy roots lately. Some have Pythium root rot as well, some appear to be in serious decline just from the physiological stress.

We already posted a bunch of information about managing rootzones and some tips on what to do in the fall and in the future, so I won’t go into that here. Glance back at our recent posts. You might also like to read pages 6-7 on the following website by Paul Vincelli and Gregg Munshaw which discusses managing summer stress in putting greens:

http://www2.ca.uky.edu/agc/pubs/ppa/ppa1/ppa1.pdf

Here is some layering in several recent samples. I know it can be tough to convince golfers to let you aerify, but the consequences of NOT aerifying can be deadly when summer weather strikes.

032

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This is an older push-up green with drainage issues in all this wet weather:

010 011

Here is a series of photos showing Pythium root rot and root decline symptoms:

Slide1 Slide2 Slide3 Slide4 Slide5

Here is a field shot of the site that goes with the microscope pictures above:

Presentation1

Here is one more set of photos showing layering and decline. This site had root decline, Pythium root rot, algae, and some anthracnose crown rot. Those factors all like to co-mingle and cause problems. This superintendent said they are working on improving some drainage and rootzone issues that built up over time.

021  027 IMG_20150730_100237320 IMG_20150802_083806451 IMG_20150803_113824539

Turf and ornamentals field day, 2015

(Megan Kennelly, KSU Plant Pathology)

Thanks to everyone who came out to Field Day last week. Thanks to the vendors for supporting the event. Thanks to the staff of the K-State Research and Extension Center – Olathe for your help.

Here are some photos taken by Linda Parsons and Cortney Nagel. Christy Dipman has also posted these on the Kansas Turfgrass Foundation Facebook page. Thanks to all 3 of you for taking and sharing these images.

1 2 3 4 5 6 7 8 9 10

Water Management on Greens with Soil Moisture Sensors

After last week’s posts, I got several follow-up questions by phone and email on how to use moisture meters. Dr. Bremer is our microclimate guru, so I asked him to provide some pointers. – Megan Kennelly

 

How much water is too much or too little for your greens?

 

By Dale Bremer

As Dr. Jack Fry discussed in his recent article on this blog Good Water Management Will Help Get Greens Through Summer Stress, too much or too little water can be detrimental. I thought I would follow up with a few practical tips on how to determine the correct amount of water for your green using a soil moisture sensor that determines volumetric water content. The most common soil moisture sensor is probably a TDR (time domain reflectometry) such as the one shown in Figure 1. Keep in mind that different depths (lengths) of probes are available, and that you are primarily interested in measuring soil moisture in the root zone; any moisture that is below the root zone is unavailable to the plant. The depth of the root zone may vary during the summer (shallower in midsummer, deeper in spring and fall), but a good compromise would probably be the 3 inch probes.

Fig1

(Figure 1)

 

Ideally we should avoid constantly saturating soils with water. Instead, allow them to dry down to a predetermined level of soil water content just before the onset of drought stress symptoms. By definition, soils are saturated when 100% of the soil pore volume is filled with water. After irrigation, the soil will eventually reach field capacity, which is the amount of water remaining in the soil after free drainage has ceased. At field capacity, soils have good aeration but also have sufficient water for plant use. General guidelines for the volumetric water content at field capacity are 15-20% in sandy soils, 35-45% for loam soils, and 45-55% for clay soils (1).

On the other end of the scale, permanent wilting point is the soil water content when plants wilt and don’t recover when the soil is rewetted. Obviously this should be avoided in a green! Textbook values for volumetric water content at the permanent wilting point are 5-10% for sandy soils, 10-15% for loam soils, and 15-20% in clay soils.

However, for a number of reasons soil water content values at field capacity and permanent wilting point may vary from the textbook values for your green. This could be caused by differences in sand particle size, organic matter content, age of a green, etc.

A simple way to determine how much water to apply to your greens is to calibrate your soil moisture probe to your soils with the following steps:

  1. Irrigate the turf thoroughly, then take readings with your soil moisture sensor one hour later. Measure in several spots around your green, perhaps even in a grid pattern as you see fit.
  2. Take readings twice daily and note visual stress symptoms of the turf.
  3. Continue taking readings until turf shows symptoms of drought stress.
  4. Once these levels have been determined, use them help guide future irrigation events.
  5. Calibrate for each soil type.

My colleagues at the University of Arkansas (Doug Karcher and Mike Richardson) (2) used this method on native soils and on 1-year old and 10-year old USGA greens and came up with the dry down curves in Figure 2.

graph

Although soil moisture levels in the 10-year old green are higher than the 1-year old green, it is likely that drought symptoms begin at a higher soil moisture content in the 10-year old green; the same is likely for the native soil. This illustrates why it is a good idea to calibrate separately for different soils and for greens that may differ in age. It’s also important to note that drought threshold levels may change through the year, as the root system changes (as alluded to above). For example, a shallow root system in midsummer may require that irrigation be applied at a higher soil water threshold because roots are not able to “mine” water deeper in the soil as they may have earlier in the growing season.

References:

  1. http://nrcca.cals.cornell.edu/soil/CA2/CA0212.1-3.php
  2. http://www.stma.org/sites/stma/files/Conference/2012_Conference/Karcher.pdf