The University of Missouri recently held a Turfgrass and Landscape Field Day on July 30th, 2019 at their South Farm Research Center. They shared an update on their website, covering weeds, billbugs, diseases and bees.
Find more about their field day program in this link.
Here is the link for their Field Day Booklet.
(Megan Kennelly, KSU Plant Pathology)
Around this time every year we all look forward to early September. Often Labor Day weekend marks the end of “summer diseases” and the beginning of fall repair and renovation to our cool-season grasses.
Moisture and humidity continue to trigger turf diseases. Here are a few recent photos:
Brown patch in tall fescue, with mycelium present on a wet, humid morning. The first photo shows the characteristic lesions. As I write this on Friday Aug 16 there is a stretch of hot days and very warm nights ahead, so this disease may continue. But September is not far away…
Dollar spot in an untreated bentgrass area:
The photo above is a worse-case scenario, with a susceptible cultivar untreated. If you are having breakthroughs, review your fungicide regime and maybe your N regime, as low N can make this one worse (but too much is a problem, too!). Check your calibration and coverage. If you’ve never read it, read the dollar spot section starting on page 14 here:
http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf
Unlike brown patch, dollar spot loves the more moderate temps of September, so this one does not fade away after Labor Day. So don’t let your guard down yet.
Another issue I’ve been seeing lately is continued problems with saturated roots, and there were more heavy rains this week. The wet soils deprive the roots of oxygen plus they hold heat, so turf does not have any “chill out time” overnight. Organic matter in the profile makes it worse. On top of the physiological issues, those wet soils can trigger Pythium root rot and sometimes anthracnose crown rot comes in on top of that.
For more details, you can check out the report this week from our great neighbor Dr. Miller here:
https://turfpath.missouri.edu/reports/2019/08_15_19/
Or here:
Finally, another issue I’d like to mention is hydrophobic soils. Despite all the rain, hydrophobic soils/localized dry spot can still occur.
Here is what localized dry spot can look like, and it can come on fast.
Keep an eye on your soil profile so you can stop this damage before it starts. When you get damage to the extent shown in those two photos above it is a long road to recovery.
To check for localized dry spot, pull up some cores and use the “droplet test” by putting drops of water on the plug. If the drops just sit there, not wicking in, you have a problem. The soil is water-repellent.
Sometimes there is a defined hydrophobic layer with normal soil above and/or below, so check at different depths, all the way down the rootzone:
You might also notice water beading up on the surface and not wicking in.
You don’t want this to sneak up on you. Keep an eye on your soil profile, especially locations with a history of problems. Aerification and use of wetting agents can help get moisture where it needs to go.
By Judy O’Mara
Declining Oaks...are not that easy to sort out. There is an assumption that if an oak tree is dying it must be due to a disease. That is usually NOT the case. Most of the poor growth that we see on oak trees in Kansas is generally due to a combination of site factors and environmental extremes. 2018 and 2019 provide back to back examples of weather extremes. Add in site factors like tree planting depth (too deep), construction damage, heavy soils or compacted soils that drain poorly, sandy soils that don’t hold on to water very well, and trees can develop root systems that are not as vigorous as they should be. The result is a situation where trees are prone to declining under weather extremes – and Kansas is all about extreme weather.
A look at some weather data for Johnson County (Olathe, KS) provided by the K-State Weather Mesonet shows that the 20yr average annual precipitation is 40.04” for that location. At a glance it is easy to see that some years run wetter than average and some years are drier than average. I picked the Johnson County, KS location to highlight because we frequently get oak tree samples in the K-State Plant Disease Diagnostic Lab from the Kansas City area with questions about disease.
2018 was a dry year due to a winter drought and we saw trees decline across the state, including quite a few oaks from the Kansas City area. There was below average precipitation between November 2017 and September 2018. This weather snapshot also shows extreme weather during 2019, particularly during April and May. Saturated soils resulting in root damage and tree decline has been a common problem this year. Young trees and shrubs are particularly at risk due to smaller root systems. In many cases, damage wasn’t immediately apparent until June or July when higher temperatures put a greater demand on the root system. So bottom line, extreme weather patterns frequently play a role in the health of our landscapes.
That said (most oak problems are not due to disease), we have picked up two different oak diseases in the Kansas City area this summer that have the potential to cause tree decline, Hypoxylon canker and oak wilt.
Hypoxylon canker, also known as Biscogniauxia canker (Biscogniauxia atropunctata; B. mediterranea) is a disease common on oak trees throughout Kansas. It is considered to be a stress disease, usually associated with drought stress. Trees showing symptoms in 2019 were likely triggered by the dry growing conditions of 2018.
The initial symptoms of Hypoxylon canker are a tan or silver fungal mat on the trunk of the tree. This light colored surface layer quickly wears off and exposes a black crusty mass that looks like asphalt. Leaves turn yellow and shed and infected trees generally die within the first year. By the second year the dead oaks slough off the remainder of their bark. The best protection against Hypoxylon canker is to avoid stress. This starts with planting into well-drained sites and providing deep, regular watering during prolonged periods of dry weather. Also take care to avoid damage due to construction activities.
Oak wilt (Bretziella fagacearum) has been picked up in a couple of red oak trees in the Kansas city area (Johnson County, KS) this summer. It is an occasional problem on red oaks and pin oaks in northeast Kansas and in counties along the Missouri state line.
Oak wilt causes a partial leaf scorch (brown at the leaf tip and green at the base). Beneath the bark tissue, the disease produces dark brown streaks in the sapwood (see photos). Oak wilt on red oaks tends to start on a major limb or in a section of a tree and then progress until the tree dies, usually within a season.
The disease can be spread by sap feeding insects so it is important to avoid pruning oaks between April-June. Oak wilt can also spread to nearby red oak trees through roots that have fused.
There is no cure for the disease. Infected trees should be removed and destroyed. The wood should not be kept for firewood. If there are red oaks nearby, the root grafts between the trees should be severed. Healthy red oaks nearby may benefit from a fungicide injection.
The best time to test for oak wilt is when trees are freshly wilted, generally in the spring.
More information on oak wilt can be found at the K-State Horticulture Information Center. Link is listed below:
Common Oak Diseases in KS
Less common oak diseases in KS
Odd but interesting oak problems in KS
A huge thank you to everyone who attended the 2019 Turfgrass Field Day in Olathe, KS. Our morning was filled with rain, but most attendees waited it out to learn more about the Turfgrass research + insect/disease updates from K-State specialists. The BBQ lunch was a big incentive for waiting it out too… 🙂
We wanted to share a few pictures from the event. There were 8 different stops at the field day. Here are the highlights:
By: Judy O’Mara
If you drive around town you will notice that most ornamental pear trees have orange leaf spots. It can look pretty dramatic. This is a fungal disease called pear rust (Gymnosporangium globosum). It is part of the complicated group of cedar rust diseases that are common in Kansas which cycle back and forth between cedar trees and their alternate host (in this case pear trees). By the time you see the symptoms it is too late to manage the disease. Preventive fungicides can be applied in the spring during the months of April and May.
A nice fact sheet on this disease can be found at: https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Pear%20Rust.pdf
I look forward to the annual exploding London plane trees (and sycamore) on the K-State campus. Sometime during early to mid-July the outer bark slips off the tree…explosively. Bark pieces can wind up 20 feet away. The first time I saw this interesting event (30 yrs ago), I was worried that the tree was going to die. I’ve since learned that this is just a normal growth habit of the tree.
My colleague and I were walking through a landscape this week and she saw this long, tan linear symptom on some hosta leaves. We both knew immediately what it was caused by…Hosta Foliar Nematodes. The nematodes in the tan narrow lesions are limited by the veins, so symptoms are long and blocky. This disease requires really wet conditions to thrive and spread.
Here are some interesting facts about foliar nematodes. They are microscopic roundworms and can survive on leaf tissue or in the soil. They can complete their life cycle in 2-4 weeks. The nematode has the ability to survive in a dormant state as a fourth stage juvenile for up to two years. Spread of foliar nematodes is by infected leaves touching other wet leaves. The disease is unattractive but rarely kills the plant. Sanitation of infected plants will help to clean up the problem
Missouri has a nice article on Hosta Foliar Nematodes: www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/nematodes/hosta-leaf-nematodes.aspx
The KGCSA Legacy Scholarship offers educational aid to the children and grandchildren of KGCSA members. A $1,000 scholarship will be awarded. Applications are due August 27, 2019.
Eligibility
1. One or more of the applicant’s parents or grandparents must have been a KGCSA member for five or more consecutive years and must be a currently active.
2. The student must be enrolled full-time at an accredited institution of higher learning, or in the case of high school seniors, must be accepted at such an institution for the next academic year. Graduating high school seniors must attach a letter of acceptance to their application.
3. Past winners are ineligible to apply the following year. They may reapply after a one-year hiatus.
Criteria for Selection
1. Applicants will be evaluated based on academic achievement, extracurricular and community involvement, leadership and outside employment.
2. The student must submit an original essay of up to 500 words.
You can download the application at www.kgcsa.org
SCHOLARSHIP OPPORTUNITY – 2019
The Heart of America GCSA Scholarship Program offers educational aid to deserving students in the turfgrass program at an accredited college or university in Kansas or Missouri.
A total up to $5,000 is allocated each year to deserving students. Applicants will compete based on their overall qualifications determined by the Scholarship and Research Committee.
Applicants:
2019 academic term
(Must carry a 2.75GPA or higher for consideration.)
Application:
Scholarship Application – 2019
Deadline:
October 31, 2019
Submit to:
Heart of America GCSA
Scholarship & Research Committee
638 W. 39th Street, Kansas City, MO 64111
Questions:
Kim Weitzel; kweitzel@westerneda.com
(By Jared Hoyle, KSU Turfgrass Research and Extension)
Last week I came home after the KSU Turfgrass Annual Field Day that was held in Olathe, KS at the Olathe Horticulture Research and Extension Center and before I even made it into the house I knew I had rust in our back yard. The shoes in the garage were a dead give away. The shoes that my wife were wearing in the back yard were orange. This disease can occur just about anywhere, when the leaves of turf are wet and when plants are stressed they are more susceptible. We see it on perennial ryegrass but can occur on other species.
Don’t worry too much as the turf typically can grow out of it.
For more information on rust check out the KSU publication below, some past blog posts from Dr. Megan Kennelly and myself, as well as some information from Richard Jauron at Iowa State University.
https://www.bookstore.ksre.ksu.edu/pubs/EP163.pdf
https://blogs.k-state.edu/turf/tag/rust/
https://blogs.k-state.edu/turf/rust-activity-in-turfgrass/
Minimal Water Requirements of Cool-Season Turfgrasses for Survival and Recovery After Prolonged Drought
Mu Hong, Dale Bremer, and Steve Keeley
Thermal Imaging Detects Early Drought Stress in Turfgrass Utilizing Small Unmanned Aircraft Systems
Mu Hong, Dale J. Bremer, and Deon van der Merwe
High and Low Management Input Regimes Result in Similar Net Carbon Sequestration Rates in Zoysiagrass Golf Course Fairway Turf
Ross C. Braun and Dale J. Bremer
Herbicide and Application Timing Effects on Windmillgrass (Chloris verticillata) Control
Nicholas Mitchell and Jared Hoyle
Influence of Herbicide Combinations and Sequential Applications on Windmillgrass (Chloris verticillata) Control
Nicholas Mitchell and Jared Hoyle
Winter Survival of Experimental Bermudagrasses in the Upper Transition Zone
Mingying Xiang, Jack Fry, and Yanqi Wu
Evaluating Large Patch-Tolerant and Cold Hardy Zoysiagrass Germplasm in the Transition Zone
Mingying Xiang, Jack Fry, and Megan Kennelly
2017 National Turfgrass Evaluation Program Perennial Ryegrass Test: 2018 Data
Mingying Xiang and Jack Fry
MANHATTAN, Kan. – Kansas State University Associate Professor and Extension Turfgrass Specialist, Dr. Jared Hoyle says homeowners ought to be thinking about a mid-summer checkup on their lawns, which likely includes applying fertilizer and weed killer.
Many Kansas summer landscapes include warm-season grasses, namely bermudagrass, zoysiagrass and buffalograss. Each of those requires a little care in order to stay healthy through the hot weeks ahead.
“Those three grasses are not all created equal and some grow faster than others, which means we need to feed them a little bit different,” said Hoyle, an associate professor in the Department of Horticulture and Natural Resources.
For bermudagrass and zoysiagrass, Hoyle suggests applying a total of 1-3 pounds of nitrogen per 1000 square feet during a typical growing season, which is the beginning of May through the middle of August.
“You can split that up into multiple applications of a quick release fertilizer, or you could do fewer applications of a slower release,” he said. “But the main goal is 1-3 pounds of nitrogen per 1000 square feet regardless of what number or percentage product you’re using.”
Buffalograss does not require as much nitrogen. Studies at Kansas State University indicate that “about 1 pound of nitrogen per year for 1000 square feet is good,” according to Hoyle.
“It’s hard to split up a pound over multiple applications, so that’s one where you might want to look at a slow release to put that pound of nitrogen per 1000 square feet throughout the year,” he said. “You can do that right now and that will get you through the rest of the year with a slow release fertilizer.”
In addition to fertilizing warm-season grasses, Hoyle said homeowners should be looking at ways to control thatch and weeds in the lawn.
“We really like to preach that if you are going to do something with the lawn — whether it is fertilizing or watering — do it when it’s actively growing,” Hoyle said. “Right now, with warm-season grasses, if you have a thatch problem, you can tear that area up (with a verti-cutter or slicer), fertilize the lawn, and it will grow right back in. If you try to do that during the fall or spring months, there will be periods of time when the lawn isn’t growing, or delayed growth, and it could lead to more problems.”
Among weeds, crabgrass and yellow nutsedge are two of the most troublesome this time of year.
““I’m seeing a lot of crabgrass and yellow nutsedge and I blame it on the weather,” Hoyle said. “Yellow nutsedge loves flooded, compacted soils and because of periodic flooding around the state, I have seen a lot of areas that typically never have yellow nutsedge. It’s a weed to keep an eye out with the weather conditions as they have been.”
To control yellow nutsedge, look for products with the active ingredients halosulfuron or sulfrentrazone, he said.
Crabgrass that has already emerged can be treated with products that include the active ingredient quinclorac.
Hoyle noted that homeowners should be patient when applying herbicides to yellow nutsedge and crabgrass; it might take more than one application to control those weeds.
K-State’s Department of Horticulture and Natural Resources publishes a weekly horticulture newsletter with updated information on lawn care and other turfgrass issues. Residents may also contact their local extension agent.
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