By Megan Kennelly, KSU Dept of Plant Pathology
We have all been feeling the heat lately. I hope everyone has been staying safe and hydrated.
Just how hot has it been? The KSU Mesonet weather team provides a helpful summary here with interesting perspectives and historical context:
Here is one of their maps – click the above link for additional data and figures. Source: Kansas Mesonet https://mesonet.k-state.edu/
Megan Kennelly, KSU Plant Pathology
It is June 8 and summer is in full swing.
Fungicide resource:
I wanted to remind everyone of this excellent commercial guide to fungicides:
http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf
It is developed by University of Kentucky, University of Wisconsin, and Rutgers University. It is based on research and reports by universities all across the country. I mention it every year and at every turf conference. It is definitely worth downloading, bookmarking, and/or printing out.
Dollar spot forecasting resource:
The Smith-Kerns dollar spot forecasting model is available online here:
https://www.greencastonline.com/dollar-spot-solutions
You can type in your zip code and see daily disease risk assessments, based on weather conditions. It uses 5-day rolling averages of temperature and humidity to designate a risk factor. (If you want more details on how it was developed and how it works check out this article.)
Here at KSU we are doing a trial this year looking at this forecasting model as part of a multistate project led by Wisconsin. Several states are working together to examine how the model performs in varieties of bentgrass with different inherent susceptibility levels. Stay tuned for research reports in the future.
Megan Kennelly, K-State Dept of Plant Pathology
Hello everyone,
Some of our mornings have had that “tropical” feeling lately! We are getting some reports of brown patch activity in tall fescue. So far it’s more from the eastern side of the state which of course does have more moisture.
Brown patch is favored by humid weather with nighttime lows around 70 degrees or above. It can occur when the nighttime lows are above 60 though.
The disease can have distinct patches OR be “diffuse/blotch” as shown in these photos:
Patchy
That is a little confusing, right? Tall fescue can also suffer from drought, grubs, general stress, etc. So – how do you tell if it is brown patch? Take a close look at the leaf blades as shown in the photos below. First, you’ll notice that tall fescue has a lot of prominent veins with a rough texture. That is ONE way to help tell it is tall fescue and not something else.
For brown patch look for a tan spot, irregular shape, with darker brown border:
Finally, if it is very moist/dewy you might see some cobwebby fungal growth – look closely here. That dries up very fast once the sun hits and the turf dries off, though.
To help prevent the disease you can make the site less favorable:
There are a lot of fungicides labeled for brown patch. Here is a great guide for commercial lawn care:
http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf.
Brown patch is on page 12, and I will not repeat all those details here. You can click and get a ton of helpful tips right there. Keep in mind that as with most diseases preventative applications work better than after the disease has kicked in. Also – turf fungicides don’t magically turn the turf healthy again. New, green grass needs to GROW and when we hit full summer stress that is slow to happen.
Finally, if you need help with a turf diagnosis you can email me (kennelly@ksu.edu) and/or send a sample to me here at KSU via the Plant Diagnostic Clinic.
Quick tips on a good sample:
From the KSU Entomology News
In May of 2021, the Insect Diagnostics program was brought back into service in an all new digital format. Members of the public seeking assistance identifying an insect can access the Insect Diagnostics ID Request Form online. After providing observation information such as location and date of the sighting, followed by answering a set of questions intended to help with the identification process, one can then upload up to 3 photos and submit the form. The inquiry is then forwarded on to one of the entomology extension specialists. Within a few days, usually less than two, the identity of the insect along with appropriate life history information and/or control measures is then sent to the client by email or phone. The online submission process takes only a few minutes and can be accessed with desktop computers and mobile devices. If you need insect identification assistance, submit a request here:
https://entomology.k-state.edu/extension/diagnostician/
| Anthony Zukoff Extension Associate – Entomology
Southwest Research and Extension Center Garden City, KS |
Direct link to KSU Entomology news: https://entomology.k-state.edu/extension/newsletter/index.html
(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:
http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf
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:
https://www.turffiles.ncsu.edu/diseases-in-turf/pythium-root-rot-in-turf/
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.
(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:
Dr. Raymond Cloyd from KSU Entomology has observed some activity of the Eastern tent caterpillar. You can read more about it on the KSU Entomology blog.
Dr. Raymond Cloyd from KSU Entomology has developed a new publication related to Japanese beetle, a serious pest of turf and landscape plants.
You can find the publication by clicking here: Japanese beetle: Insect pest of horticultural plants and turfgrass.
“This growing season may be a challenge for producers/applicators in more ways than one. With the critical need for N95 respirators for health care workers, it is anticipated that applicators may experience a shortage of personal protective equipment (PPE) that will be available to use this growing season if not previously purchased.”
You can read full article on the KSU Entomology Blog
Hello everyone here are some Covid19 updates that may be useful to your operations.
Please watch for additional information from state and local authorities. As you know, the situation changes daily in terms of case loads, etc.
No-touch golf
At present, golf courses in Kansas are open related to policies about “engaging in an outdoor activity.” However, all the rules described in this document must be followed. Click the following link to open the document: 20-16-1 Guidance v2 – Essential Activities Functions
Best practices for sharing vehicles
The following document was developed by Colorado State related to farm vehicles but many of the health and safety practices make sense to the “green industry.” Please be sure to watch for any additional guidance or policies from state or local authorities in your area. This is just a general set of practices to consider. You can click for a larger view.
This form is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
