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Category: Diseases

Help us help you – Submitting a sample to the KSU Plant Disease Diagnostic Lab

You think you have a plant problem, and you want some help. So, now what? You’ve heard of the diagnostic lab, but you aren’t sure what to do.

Here are some tips on submitting a turf sample

Here are some tips on submitting a tree/shrub sample

Two nice-sized turf plugs, at the transition of healthy and damaged? YES! That is great:

Tiny branch, smaller than my pinky? NOT! This is not ideal:

So, check out those links above for the guidelines on what to send.

If you have more questions feel free to email me at kennelly@ksu.edu

Wet and humid = slime mold weather

Hey, what’s that stuff? Slime molds! They can look pretty alarming, and they can pop up seemingly overnight. They are pretty harmless, and you can read more HERE and if you would like a fascinating glimpse into how these organisms work there is a short video clip HERE called “Are you smarter than a slime mold?”

 

Some other shapes and colors of slime mold:

 

Brown Patch Resources

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Tall fescue [Festuca arundinacea Schreb.] is one of the most predominantly used cool-season turfgrass species in the transition zone. Its deep root system and coarse textured leafs lend to its ability to withstand drought, heat, and wear stress. Although it is well adapted to survive the summer months in Kansas, it can be susceptible to injury from disease. Brown patch [Rhizoctonia solani] is a disease that can damage leaf tissue, shoots, and the crown of tall fescue during the summer months. This disease is most prevalent during periods of high humidity, high temperature (above 80°F), and high nitrogen levels. During the mornings mycelia can be seen forming a “smoke ring” around the affected area. Applications of preventative fungicides have proven to be a successful management strategy in reducing the occurrence of brown patch incidences in tall fescue stands.

Here are some resources from the past about brown patch!

Last year Dr. Fry was seeing brown patch in May.  With moisture and warm nights brown patch can start to develop.  http://blogs.k-state.edu/turf/im-not-ready-to-be-thinking-about-brown-patch-jack/

There are many products out there for brown patch control in turfgrass.  Which one is right for you.  Here is a quick update on research that was conducted at Olathe on some brown patch products. http://blogs.k-state.edu/turf/best-way-to-get-your-turf-noticed-brown-patch/ 

Do you know what brown patch looks like?  Do you know how to tell the difference between turfgrass stress and the disease.  Dr. Kennelly can show you the difference. http://blogs.k-state.edu/turf/is-this-brown-patch/

K-State Publications

Commercial Management of Brown Patch – https://www.bookstore.ksre.ksu.edu/pubs/EP146.pdf

Homeowner Management of Brown Patch – http://www.plantpath.k-state.edu/extension/documents/turf/Brown%20patch%20%20homeowners%202016.pdf

Don’t miss the 2017 KSU Turfgrass Field Day – August 3rd

The next Turfgrass Field Day will be held on Thursday, August 3, 2017 at the John C. Pair Horticultural Research Center, Wichita.
The KTF Turf Field Days are a great way to see and learn about the turfgrass research at K-State first hand. The events are held annually in the summer at the turfgrass research locations of Kansas State University.

The Field Day qualifies for recertification credit hr for commercial pesticide applicators.

You can now Register and Pay Online at  https://2017turffieldday.eventbrite.com
or you can register by downloading, printing, and mailing go to the 2017 Field Day brochure.

Exhibitors can get more information from the Exhibitor Registration Form.

Schedule of the 2017 Field Day 
8:00 a.m. Registration (coffee, tea, donuts)
Visit Exhibitors
8:45         Welcome
9:00        Tour Highlights:

*Turfgrass Weed Control Update
*Turf & Ornamental Diseases
*Bermudagrass & Zoysiagrass Cultivar Selection
*Using Kansas Mesonet to Imrpove Accuracy in Landscape Irrigation
*Right Plant, FROM the Right Place
* Prairie Star Flowers
*Tall Fescue NTEP
*Turf & Ornamental Insect Control
11:30       Lunch

After Lunch

  • Equipment Demonstrations

If you have any questions, please contact,
    Christy Dipman 
    1712 Claflin, 2021 Throckmorton Hall
Manhattan, Kansas 66506
Phone: (785) 532-6173
Fax: (785) 532-6949
Email: 
Christy

 

 

A queasy feeling leading into summer – turfgrass root health

Got layers of organic matter in your putting greens? That stuff holds water, which holds heat, and serves as a “risk factor” for root health.

It’s another week with rain in the forecast in many parts of Kansas. We’ve talked about this before on the blog many times – root health is key to getting through our tough summer months.

Do you have drainage problems? Do you have a buildup of organic matter? How do your roots look now? Sites with “pre-existing conditions” are the first ones to crash when the weather gets nasty.

 

Moisture management can be tricky, but there are tips and tools to help you. Here are links to two articles from last year:

By Jack Fry: – general tips for water management:

https://blogs.k-state.edu/turf/good-water-management-will-help-get-greens-through-midsummer-stress/

By Dale Bremer – using moisture sensors:

https://blogs.k-state.edu/turf/water-management-on-greens-with-soil-moisture-sensors/

Reducing summer stress on putting greens:

I’ve mentioned this fungicide guide (below) many times over the years. One of my favorite parts is the section starting on page 6 about reducing summer stress. Quick, off the top of your head, how many practices can YOU think of to reduce summer stress? The guide lists SIXTEEN steps to consider. Maybe you can’t do them all, but I bet you can try at least one new thing you have not tried before.

Here is the link (scroll to p. 6 for the summer stress)
http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf

Pythium root rot:

My excellent colleague at U of Missouri, Dr. Lee Miller, has recently posted some very helpful info about Pythium root rot. You can find those articles here:

http://turfpath.missouri.edu/reports/2017/update05_26_17.cfm

http://turfpath.missouri.edu/reports/2017/update05_11_17.cfm

Powdery mildew in turf

Turf powdery mildew thrives in shady sites during cool, humid weather. We have had a lot of cool, moist days with temps in the 50s and 60s which is perfect for powdery mildew. The disease is often temporary, disappearing when hotter, drier weather kicks in.

The following photos are courtesy of my excellent colleague Chuck Otte, County Extension Agent, Ag & Natural Resources, Geary County. He confirmed that the site is shady.

It’s a fescue/bluegrass blend. To my eye, it looks like the Kentucky bluegrass is affected more than the fescue.

This next photo is a super-zoom of powdery mildew through the microscope. The photo is from squash powdery mildew, not turf powdery mildew, but turf powdery produces similar structures – long chains of spores. The spores are blown by wind. When they land on a new, susceptible plant and IF conditions are right, they germinate and infect.

We see turf powdery mildew in spring and fall. A change to less humid, hotter weather will slow the disease.

Turf powdery mildew is one of the many diseases covered in the 2017 Turfgrass Fungicide Guide.

There are fungicides labeled, but for most of them little is known about the efficacy. The DMI fungicides have efficacy, but it can be hard to reduce disease once it is underway. Also, as I just mentioned, a shift in the weather will slow the disease. If a site has a chronic, ongoing powdery mildew options include improving airflow and sun exposure or renovating to a less susceptible type of turf or groundcover. Those cultural practices and site management tweaks are your best bet.

Anthracnose in shade trees

Here is a quick update from Ward Upham and the Horticulture News:

We are starting to see anthracnose on sycamore. Anthracnose is a fungal disease favored by cool, wet weather. Young leaves may wither and turn black. On older leaves, look for brown areas that follow the major veins of the leaves. In some cases, the petiole (leaf stem) is infected, which causes leaf drop. The leaf may look perfectly fine, so look for browned areas on the petiole.
In severe cases, the tree drops heavily infected leaves and may be completely defoliated. Healthy trees will leaf out again in a few weeks. Defoliation this early in the year does not affect overall tree health. Trees have plenty of time to produce new leaves and make the energy reserves needed to survive the winter.
Other types of trees that are affected by anthracnose include birch, elm, walnut, oak and especially ash. Anthracnose seldom causes significant damage to trees in Kansas, so chemical controls are usually unnecessary. Also, fungicides do not cure infected leaves. Applying fungicides now will not help.

 

For a detailed overview of anthracnose diseases of shade trees, you can check out the free online pdf version of Diseases of Trees in the Great Plains. I’ve mentioned this book before – it is a great resource!  Here is the link, and the anthracnose part is the section section, on p. 22 of the pdf.

Anthracnose is also covered in our Tree and Shrub Problems of Kansas book.

Spring turf disease potpourri

 

Wet, cool weather is favoring continued activity of large patch and other spring diseases. If you have not downloaded it yet, be sure to check out the 2017 fungicide guide from Vincelli et al.

For a superb update on large patch, dollar spot, spring dead spot, and root problems, you can roll on over to the Missouri Turf Pathology Report .

Here is some large patch in our research plots:

 

Just for fun, here is some fairy ring activity. I walk past this spot a lot, and those mushrooms popped out after a recent rain.

And also just for fun here are two panoramas of Rocky Ford! You can click to zoom and imagine birds chirping and a soft spring breeze in the air… ahhhh….

Zoysia research – a 2 minute video tour

Here is a brief tour of our zoysiagrass progeny evaluation plots. The study is in collaboration with Texas A&M, Purdue, and several other universities across the region. It is funded by the US Golf Association. PhD student Mingying Xiang is working on this as part of her dissertation research.

Here is the link to a brief video on YouTube.

Sorry about the wind noise! I tried on Monday, and it was even worse, so this is at least better than my first attempt. We can’t be too picky about the wind here in Kansas, right?

Here is a link to a post from last fall where we talk about the inoculation method.

And here is a checkerboard of inoculation points in Meyer zoysia, from a few years back:

Dothistroma needle blight in pines … or not?

We recently posted about pine wilt and pine tip blight. To round out the big three pine diseases, below are a few quick notes about Dothistroma needle blight. For a review of all three of these diseases, plus natural needle drop, you can check out Pine Diseases of Kansas. (Click that link to download a free pdf with lots of photos and management information.)

Dothistroma needle blight is common in Austrian and Ponderosa pine. It can occur on Mugo pine, too.

Dothistroma spends the winter in infected needles. During wet conditions in late spring/early summer the fungus infects new needles.

Here is a photo of the fungal fruiting structure – the little black lump peeking out from under a flap of needle tissue:

We have been seeing those in the past couple of months on needles that were infected last year. December through April is when those fruiting bodies start to pop, allowing us to make a diagnosis.

Those fruiting structures produce spores that spread in rain to infect new needles. This often occurs during wet, mild weather in late spring, early summer (but can occur all summer). Those needles eventually show a partial needle scorch, with the base staying green. Each needle is a little different, depending on where the fungus got in there. The photo below shows some needle spots and banding and then the browning (necrosis) from the infection point outward.

 

On a tree, this shows up as partial browning, then complete browning, of the needles one year back on the branch:

The older, needles eventually drop off, leaving just a one-year tuft of the newest needles. The branch looks like a broomstick or a lion’s tail:

The damage tends to start in the lower part of the tree and work its way up. The disease is more likely in older trees. Mature, overcrowded windbreak trees are susceptible. Normally, pines keep several years of needles. If all those inner needles drop the tree has less capacity to do photosynthesis and it can weaken. Each little needle is like a solar panel, and fewer solar panels means less energy.

What do you think about this tree?

It is a young tree, and the damage is more top-down, not bottom up. So the overall pattern does not seem right for Dothistroma. Remember – with Dothistroma the disease usually starts at the lower part and works up, with older trees more prone to the disease.

Let’s take a closer look. What do you see? Or NOT see?

The damage is pretty uniform, with each needle looking quite similar. Compare it to that photo farther up where each needle is a little different. Plus, there is no spotting/banding. My guess is this is environmental stress. Pines can definitely get the moisture sucked right out of them during dry winter winds.

To know for sure, samples can be submitted to our Plant Disease Clinic either directly or (even better) through your local K-State Research and Extension Office.

Need more details? Remember our publication about Pine Diseases in Kansas where you can find more information about diagnosing and managing Dothistroma and the other pine diseases.