Kansas State University


K-State Turf and Landscape Blog

Month: July 2020

Root decline, Pythium root rot, and anthracnose in recent samples

(Megan Kennelly, KSU Plant Pathology)

Here is a sample that came into the lab recently:

You can see turf decline, and if you look closely you can see some dark green algae in the brown area. Algae often indicates poor drainage. This site is in a low area with poor airflow. The site has a lot of underlying stress.

Here is a view of the washed-off roots sitting on the dissecting microscope. They should be a creamy white but instead they are more of a brown color. They were mushy in texture as well.


Finally below is a closer view in the compound microscope. You can see how the roots are dark. Healthy roots are much more clear/transparent. These are also lacking fine root hairs, and the outer tissues have sloughed off.

These symptoms occur frequently in sites with poor drainage. The roots sit wet, and oxygen flow is disrupted. The wet soil holds heat overnight as well.

The environmental stress alone can cause major root decline and turf damage.

In addition, these conditions can trigger Pythium root rot. (This particular sample did have some Pythium as well, I just had a hard time getting a clear photo). And, these stress conditions can also lead to crown anthracnose. I’ve seen a couple of samples with that disease lately as well. Anthracnose is more likely to chow down on turf that is already stressed.

Here is a link to a publication I’ve mentioned countless times on this blog:


There are excellent sections on individual diseases, but there is also a detailed section about summer stress on page 6. Many of the stress-reducing practices listed there will also reduce susceptibility to diseases.

That publication does not discuss Pythium root rot (PRR). (It does discuss Pythium root dysfunction (PRD) which is related but different.) Here is a great resources on PRR:


Each year, we say, “I hope this August isn’t a bad one”. This coming week there will be some lower highs (low to mid 80’s) and “lower lows” (mid-60’s overnight, and even some upper 50’s! Woohoo!). Cool temps will be a blessing. However, continued rain may exacerbate drainage problems.

Managing the diseases is important, but it’s critical to address the physiological/environmental stresses as well or the turf can still suffer major decline this time of year.



Localized dry spot in sand-based putting greens

(Megan Kennelly, KSU Plant Pathology)

When hot dry winds meet hydrophobic (water-repellent) soil we can get “localized dry spot” in turf. The damage can develop quickly.

Water should wick in quickly. However, when the soil is hydrophobic the droplets sit there on the surface, and they don’t soak in:

The soil becomes hydrophobic due to a build-up of water-repellent waxy substances around the soil particles.

Here are some examples of what it can look like. It often takes odd shapes with unusual wispy/hazy edges:

Below are a couple of photos from a recent sample to the KSU diagnostic lab. You can see hydrophobic area a couple of inches down in the profile. You can also see the damaged turf in the background. The submitter said it was quite patchy around the green. It’s important to check your moisture levels regularly. When you do, check it in multiple places. You can even go high-tech with a moisture meter. For more information you can check this article from a few years back, Water Management on Greens With Soil Moisture Sensors.


Thatchy soils are one predisposing condition, and you can see the thatchy layers from this particular site here (though this particular plug was NOT hydrophobic):

Thatch management and wetting agents can help prevent and alleviate localized dry spot. There is some USGA info about localized dry spot here:



New Podcast by Kansas Forest Service

By Brooke Garcia

Tim McDonnell, Community Forestry Coordinator for Kansas Forest Service, and Gary Farris, Arborist for the City of Wichita, recently recorded a podcast that highlights the importance of community forests. They discuss how Kansas also faces challenges in regards to protecting urban forests.

Listen to the podcast here: https://kansasforestservice.libsyn.com/more-than-beautification

Abundance of Caterpillars in the Garden

By Frannie Miller

This post has been provided by the Extension Entomology e-Newsletter.

This week as I have been out in my own yard and garden I have noticed an abundance of different types of caterpillars. Identification of caterpillars can be difficult because so many of them look really similar, but often if you know what plant they feed upon it will give you a clue.

The first image is of a caterpillar sent to me by a friend asking what it was. She found it feeding on her pansies, which were a hold over plants from spring. These caterpillars are known as pansyworms. They usually grow to be 1 ¼ inches long with a characteristic deep-orange color with black striped sides which feature spines. These caterpillars will take bites out of the leaves, but the resulting variegated fritillary butterfly will add color to the garden.

Panysworm image: Courtesy of Cheryl Boyer

Then I found a few yellowstriped armyworm caterpillars feeding on some of my flowers. I picked them off as I did not want them to feed on those particular plants, but allowed them to feed elsewhere. These caterpillars turn into a somewhat drab grayish-brown moth.

Yellow Striped Armyworm

Finally I spotted a mass of small caterpillars feeding on sunflowers in the garden. The sunflowers were not ones I plants and had come up as volunteer so I have decided to let the caterpillars eat on these plants. It is difficult to for me to identify the exact species from a picture, but they will turn into some sort of checkerspot butterfly.

I have chosen to not use any insecticides to control these particular caterpillars, but options such as Bacillus thuringiensis subsp. kurstaki (Btk) and spinosad can be used when caterpillars are small. If you are going to use these products, remember to read and follow the label.

Checkerspot Caterpillar

Sometimes we don’t notice the caterpillars until they are larger and hand picking may become the best control option.

The damage caused by Japanese Beetles

By Brooke Garcia

Japanese beetle is popping up throughout most of Kansas, and it is feeding on many common landscape plants including roses, littleleaf linden, Virginia creeper, and grape. The Extension Entomology e-newletter recently posted a blog that highlights information related to management, chemical treatment, as well as biological information about the beetles. They are one of the most destructive insect pests on horticultural plants, and they cause a lot of problems for professionals and homeowners alike in landscapes and gardens. Raymond Cloyd also notes that, “the larva or grub is a turfgrass insect pest in home lawns, commercial settings, and golf courses.”

To read more, visit the Extension Entomology post, Japanese Beetle Adults Are Here!

Japanese Beetle Adults Feeding On Leaf (Auth–Raymond Cloyd, KSU)

Tips for submitting a ‘digital sample’ to plant disease diagnostic lab

By Lucky Mehra

When it comes to plant health, physical samples are best. However, sometimes it is not practical to send physical samples, such as with large trees or shrubs. A digital sample can be a good alternative or a good first step. By ‘digital sample’ we mean submitting digital images of the plant problem to the KSU plant disease diagnostic clinic.

Consider the following tips to take the photos and provide all the relevant information to help us diagnose the problem quickly and correctly.


The main component of a ‘digital sample’ is the set of digital images itself. Take the following types of pictures to help us understand both the ‘big’ and ‘small’ picture of the problem. Make sure that the plant or plant part is in focus when taking pictures. Some phones are pretty good at auto focus, but most of the time you will need to tap on the screen at the point of interest to guide your camera to focus at a particular point.

  • Take pictures from a distance to give us the landscape view or the ‘big picture view’. It should include the whole tree/shrub along with neighboring plants (Fig. 1).

Fig. 1. The Hawthorn tree in the foreground has leaf spots. This image is to give an overall view of the landscape. For example, proximity of the tree to the concrete and adjoining trees.

  • Photo of the affected plant(s) i.e. the plant(s) showing the problem.
  • Photo of the affected plant part, whether it is leaf, flower, stem, twig, or root (FIg. 2).

Fig. 2. Affected leaves of the hawthorn tree.

  • Try to take a close-up shot of the problem symptoms (Fig. 3). If there are signs (actual parts of the pathogen i.e. fungal mycelium or other structures) present on the plant part, try to zoom in, tap to focus, and then take the photo. Take multiple photos to ensure that you will have at least a few good quality ones. If you have access to a microscope, you can bring the affected plant part to your home or office and focus it under the microscope. With some patience, you can also take really good macro shots with your phone through the eyepiece lens. Many of our students take photos this way in the lab. 

Fig. 3. An example of close-up images of a hawthorn leaf (top side of leaf on the left, and underside of leaf on the right) with yellow spots taken with a phone camera, without any additional lens attachment.

Additional essential information

Sometimes, the plant problem is very peculiar, and it is easy to identify by just looking at the photos you submit (e.g. yellow spots on hawthorn leaves shown above are the symptoms of Cedar-hawthorn rust); however, most of the time it is not possible to diagnose a problem only based on photos. We need much more information from you to help us with the correct diagnosis. Provide as much information as you can. Please see below for the type of information that will be useful to us when making the diagnosis.

Site history and pattern

Make sure to provide information about the site where the shrub or tree is located. That information may include soil type if known, soil pH, slope, distance to the concrete sidewalk or road etc. 

Are there any drainage problems? Is this the only plant affected? Are other plants of the same species affected? If yes, what is the pattern of these plants in the landscape i.e. is there a cluster of affected plants or the distribution is random? Are other plant species affected?

Plant pattern

Tell us about the affected plant part whether it is leaf, stem, flower, twig, stem or root. Additionally, report the location of symptoms on the plant. Some problems tend to occur on younger leaves, others are specific to older leaves. All this information can help us rule out some issues and narrow down the diagnosis.

Timing of the symptom appearance.

Was there any weather event such as temperature (too hot or too cold) or moisture extremes (e.g. heavy rainfall) prior to the symptom development. We can download these data from a local weather station as well, however, rainfall events can be non-uniform over the whole area covered by a weather station. So if you have onsite information about the weather data, report it to us.

Chemical history

Any history of chemical or fertilizer application should be provided. This can help the diagnostician in figuring out if the problem is arising due to chemical exposure or due to a biotic agent.

Euonymus Scale

By Brooke Garcia

This is the time during the summer season when Euonymus Scale may be extra noticeable on evergreen euonymus. The scale insect will appear as small, white dots covering the planting. If you are wearing darker clothing and come into contact with the shrub, you may notice the white “debris” coming off of the plant. The plant can quickly become infested and covered with this insect. Euonymus Scale is capable of killing the plant if left untreated. Keep a watchful eye on plantings during this time. There are cultural strategies that can be incorporated into the garden to reduce the likelihood of this insect becoming a problem, but it is extremely prevalent and may require chemical treatment.

Euonymus Scale Infestation On Euonymus Plants Located Near Building (Auth-Raymond Cloyd, KSU)

For more information about the biological characteristics of this insects, as well as cultural and chemical practices that can aid in prevention and/or treatment, visit the K-State Extension Entomology post here: https://blogs.k-state.edu/kansasbugs/2020/07/02/euonymus-scale-4/

USGA Highlights Kansas City’s Professional Sports Venues

By Dr. Jack Fry
The USGA recently released a video that demonstrates how important their research support is to the turf industry.  Not only does the research they’ve supported impact the golf industry, but it also carries over to other sports and the lawn and landscape industry as well.  This video (link below) focuses on the sports turf managers at Kauffman Stadium (Trevor Vance), Arrowhead Stadium (Travis Hogan), and Children’s Mercy Park (Casey Montgomery).  Over the years, the USGA has also been very supportive of K-State’s turf research.  Not only that, the current Director of the USGA Turf and Environmental Research Program, Dr. Cole Thompson, is a K-State alum.