Kansas State University

search

K-State Turfgrass

Month: August 2019

Wild Violet Control

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Wild violet or common blue violet is a persistent perennial broadleaf weed commonly found in thin, shaded turfgrass. The plant has heart-shaped, shiny leaves and can spread by rhizomes which makes it a difficult to control weed. The flowers are deep purple or bluish purple. There are many similar species but collectively, turfgrass managers just refer to them as wild violet.

Control has been difficult but can be achieve if you choose the right herbicide and rate. Triclopyr has proven to be effective in cool-season turfgrass and is contained in many different products that are on the market. But the key is to make sure that you apply more than 0.5 lbs ae/A of triclopyr to result in effective control. Not all products that contain triclopyr when applied at the recommended rate will have enough triclopyr for effective control.

At a quick glace through the Turfgrass Weed Control for Professionals manual (Get you copy here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239) I found a table that shows the rates of triclopyr-delivered by various products at the low and high label rate. From that chart, the following are products that contain ≥ 0.5 lbs ae/A of triclopyr, when applied at the correct rate.

  • Aquasweep
  • Chaser 2 Amine
  • Chaser
  • Crossroad
  • Everett
  • Confront
  • 2-D
  • Tailspin
  • Turflon Ester Ultra
  • Triclopyr 4
  • Trycera

The take home message; To control wild violet in cool-season turfgrass use tricopyr (0.5 lbs ae/A), may different products contain triclopyr, not all products contain enough triclopyr, choose a product that when applied at the correct rate will result in at least 0.5 lbs ae/A of triclopyr.

If you are needing to control wild violet in bermduagrass or zoysiagrass; metsulfuron, sulfentrazon + metsulfuron and flazasulfuron are effective. Repeat applications are often required regardless of the herbicide.

Also, fall applications are best followed by spring applications.

Information from this post if from “Turfgrass Weed Control for Professionals” To get your copy today click here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***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

White Clover and Yellow Woodsorrel Control

(By Jared Hoyle, KSU Turfgrass Research and Extension)

White clover is one of the most common weeds found in cool-season turfgrass.  It can grow in a wide range of environmental conditions and can tolerate many of our cultural practices.   It can also spread by seeds and by stolons. White clover is a perennial broadleaf weed that has trifoliate leaves that may or may not have a wedged-shaped mark. Although it is called white clover the flowers are white but may turn pink as they age.

Because white clover can fix its own nitrogen some see it as an important species to add beneficial soil nitrogen.  There had been some work done to explore using both clover and turfgrass in a mixture in their lawns.  Others may consider it as a weed.

If you consider it a weed, fall is a great time to try and control it.  But did you know 2,4-D, glyphosate and sulfentrazone do not control white clover?

For best control herbicides that contain clopyralid, dicamba, fluroxypyr, florasulam, metsulfruon, and/or quinclorac (also controls crabgrass) provide the best control when applied in the fall.

Yellow woodsorrel (Oxalis stricta) is a perennial or annual broadleaf weed that has clover-like trifoliate heart shaped leaves.  Yellow woodsorrel most commonly spreads by seeds that are contained in a capsule that when it explodes ejects the seeds.  It can be confused with clover but has yellow flowers with five petals.  You can find this weed in a wide range of soil conditions and can commonly be confused with black medic, birdsfoot trefoil and white clover. A similar species is creeping woodsorrel but it is most commonly found in landscape plantings while yellow woodsorrel is most commonly found in turf.

To control oxalis, herbicides that contain triclopyr and fluroxypyr are very effective.

Herbicides that contain fluroxypyr include;

  • Battleship III
  • Escalade 2
  • Momentum FX2
  • Tailspin
  • Vista XRT

Herbicides that contain triclopyr include;

  • 2-D
  • 4-Speed XT
  • Battleship III
  • Chaser
  • Chaser 2 amine
  • Confront
  • Cool Power
  • Eliminate
  • Horsepower
  • Momentum  FX2
  • Tailspin
  • Three-Way Ester II
  • Turflon Ester Ultra
  • Turflon II amine
  • Triclopyr 4
  • TZONE

Always remember a healthy turfgrass stand through proper maintenance is the best weed control and can help minimize clover and yellow woodsorrel in you turfgrass.

Information from this post if from “Turfgrass Weed Control for Professionals” To get your copy today click here – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=20239

Always remember to READ THE LABEL for the correct rate, turfgrass tolerance, and specific instructions before application!!!

***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

It is that time of year to start working on your cool-season lawn!

 

(By Jared Hoyle, KSU Turfgrass Research and Extension)

It is that time of year again to start working on your cool-season lawn.  To try and cover it all, I have listed a couple posts from the past that can help you get that lawn into shape.  I also have added a list of publications. Enjoy!

Time to fertilize cool-season turfgrass

http://blogs.k-state.edu/turf/time-to-fertilize-cool-season-turfgrass/ 

 Monthly calendar for cool-season lawns for the rest of the year

http://blogs.k-state.edu/turf/monthly-calendar-for-cool-season-lawns-for-the-rest-of-2017/

 Power raking or core aeration – That is the question!

http://blogs.k-state.edu/turf/power-raking-or-core-aeration-that-is-the-question/

 The art of knowing your seed label

http://blogs.k-state.edu/turf/the-art-of-knowing-your-seed-label/

 For seeding success, pay attention to other crop on the seed label

http://blogs.k-state.edu/turf/for-seeding-success-pay-attention-to-other-crop-on-the-seed-label/

 

Publications

Lawn Fertilizing Guide – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=10639

Recycling your grass clippings  – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=701

Mowing your lawn – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=615

 Tall Fescue Lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1460

Watering New Lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1337

 Planting a Home Lawn – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=595

 Aerating Your Lawn – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=713

 Kentucky Bluegrass Lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=713

 

Check out the KSRE Bookstore for more publications – https://www.bookstore.ksre.ksu.edu/Category.aspx?id=528&catId=545

Fall Turfgrass Recommendations and Tips

By Ward Upham

Fall Lawn Seeding Tips

The keys to successful lawn seeding are proper rates, even dispersal, good seed to soil contact, and proper watering. Evenness is best achieved by carefully calibrating the seeder or by adjusting the seeder to a low setting and making several passes to ensure even distribution. Seeding a little on the heavy side with close overlapping is better than missing areas altogether, especially for the bunch-type tall fescue, which does not spread.   Multiple seeder passes in opposite directions should help avoid this problem.

A more serious error in seeding is using the improper rate. For tall fescue, aim for 6 to 8 pounds of seed per 1,000 square feet for new areas and about half as much for overseeding or seeding areas in the shade.

Kentucky bluegrass is much smaller seed so less is needed for establishment.  Use 2 to 3 pounds of seed per 1,000 square feet for a new lawn and half that for overseeding or shady areas.

Using too much seed results in a lawn more prone to disease and damage from stress. The best way to avoid such a mistake is to determine the square footage of the yard first, and then calculate the amount of seed. Using too little seed can also be detrimental and result in clumpy turf that is not as visually pleasing.

Establishing good seed to soil contact is essential for good germination rates. Slit seeders achieve good contact at the time of seeding by dropping seed directly behind the blade that slices a furrow into the soil. Packing wheels then follow to close the furrow. The same result can be accomplished by using a verticut before broadcasting the seed, and then verticutting a second time.

Core aerators can also be used to seed grass. Go over an area at least three times in different directions, and then broadcast the seed. Germination will occur in the aeration holes. Because those holes stay moister than a traditional seedbed, this method requires less watering.

If the soil that has been worked by a rototiller, firm the soil with a roller or lawn tractor and  use light hand raking to mix the seed into the soil. A leaf rake often works better than a garden rake because it mixes seed more shallowly.

Water newly planted areas lightly, but often. Keep soil constantly moist but not waterlogged.  During hot days, a new lawn may need to be watered three times a day. If watered less, germination will be slowed. Cool, calm days may require watering only every couple of days. As the grass plants come up, gradually decrease watering to once a week if there is no rain. Let the plants tell you when to water. If you can push the blades down and they don’t spring back up quickly, the lawn needs water. Once seed sprouts, try to minimize traffic (foot, mower, dog, etc.) seeded areas receive until the seedlings are a little more robust and ready to be mowed. Begin mowing once seedlings reach 3 to 4 inches tall.

Overseeding a Lawn

Tall fescue lawns that have become thin over the summer can be thickened up by overseeding during September. Start by mowing the grass short (1 to 1.5 inches) and removing the clippings. This will make it easier to achieve good seed-soil contact and increase the amount of light that will reach the young seedlings.

Good seed-soil contact is vital if the overseeding is to be successful. Excess thatch can prevent seed from reaching the soil and germinating. Normally we want 1/4 inch of thatch or less when overseeding. If the thatch layer is 3/4 inch or more, it is usually easiest to use a sod cutter to remove it and start over with a new lawn. A power rake can be used to reduce a thatch layer that is less than 3/4 inch but more than a quarter inch.

Once thatch is under control, the soil should be prepared for the seed. This can be done in various ways.   For small spots, a hand rake can be used to roughen up the soil before the seed is applied,

A verticut machine has solid vertical blades that can be set to cut furrows in the soil. It is best to go two different directions with the machine. A slit seeder is a verticut machine with a seed hopper added so the soil prep and seeding operation are combined. Another option is to use a core aerator.

The core aerator will punch holes in the soil and deposit the soil cores on the surface of the ground. Each hole produces an excellent environment for seed germination and growth. Make three to four passes with the core aerator to ensure enough holes for the seed. Using a core aerator has the additional benefit of reducing the amount of watering needed to get the seed germinated and growing. Aeration also increases the water infiltration rate, decreases compaction, and increases the amount of oxygen in the soil.

Of the three methods, I prefer the slit seeder for obtaining good seed/soil contact.  However, if watering is difficult, core aeration may be a better option.  Regardless of method used, fertilizer should  be applied at the rate suggested by a soil test, or a starter fertilizer should be used at the rate suggested on the bag.

Give Cool-Season Grasses a Boost

September is almost here and that means it is prime time to fertilize your tall fescue or Kentucky bluegrass lawns. If you could only fertilize your cool-season grasses once per year, this would be the best time to do it.

These grasses are entering their fall growth cycle as days shorten and temperatures moderate (especially at night). Cool-season grasses naturally thicken up in the fall by tillering (forming new shoots at the base of existing plants) and, for bluegrass, spreading by underground stems called rhizomes. Consequently, September is the most important time to fertilize these grasses.

Apply 1 to 1.5 pounds of actual nitrogen per 1,000 square feet. The settings recommended on lawn fertilizer bags usually result in about 1 pound of nitrogen per 1,000 square feet. We recommend a quick-release source of nitrogen at this time. Most fertilizers sold in garden centers and department stores contain either quick-release nitrogen or a mixture of quick- and slow-release. Usually only lawn fertilizers recommended for summer use contain slow-release nitrogen. Any of the others should be quick-release.

The second most important fertilization of cool-season grasses also occurs during the fall. A November fertilizer application will help the grass green up earlier next spring and provide the nutrients needed until summer. It also should be quick-release applied at the rate of 1-pound actual nitrogen per 1,000 square feet.

Power Raking and Core-Aeration

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.

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 fall apart 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.

To view these posts in the Horticulture e-Newsletter, visit: http://www.ksuhortnewsletter.org/

Keep an eye out for powdery mildew in your landscape…

By Christian Webb

As summer starts winding down, you may begin to notice some of your bedding plants developing a white powdery coat on the upper surface of their leaves. No, this is not your plants putting on a winter coat for the cool autumn nights. It’s actually caused by the infection of a fungus on the surface of your plants leaves called powdery mildew.

Powdery mildew can be commonly found developing on many types of landscape plants during the late summer. On most plants, this disease will develop on the lower leaves and move up through the canopy. The typically symptoms of the infection will appear as a white to grey dusty growth on the upper surface of the leaves. In severe cases, leave may appear distorted and the cause defoliation.

Pictured to the left: Powdery mildew on Ox-eye Daisy (Heliopsis helianthoides)

To develop, the fungus requires high relative humidity and temperatures around 70⁰F. Many woody and herbaceous ornamentals may be affected by powdery mildew. As a general rule, the powdery mildew on one host will only affect hosts in that genus. For example, the fungi that you will find on oaks trees will only affect oaks and the powdery mildew on grapes will only affect grapes.

If you are looking to control powdery mildew in your landscape, there are a few ways to protect your plants. For annuals, increasing the spacing between plants will increase airflow through the canopy create more unfavorable conditions for powdery mildew develop. Along with altering the plant canopy, consider planting resistant hosts. Replanting the same susceptible hosts will likely result in a reinfection.

Pictured above on left: Powdery mildew on Zinnia (Zinnia elegans). Right: A microscopic image of the powdery mildew spores on the surface of a Zinnia leaf.

There are labeled fungicides for the control of powdery mildew. But you consider apply any product, be sure that your infection is caused by powdery mildew. Downy mildews looks similar to powdery mildew, but are caused by a different type of organism and may not be controlled by products labeled for powdery mildew. Powdery mildew is typically found on the upper surface of the leaf, while downy mildew is associated with the underside of the leaf. For recommended products for the control of powdery mildew, please consult the following factsheet: Link.

For further assistant in identifying powdery mildew, contact your local extension office.

To find your local extension office, the list of Kansas extension offices can be found here.

Further discussion of powdery mildew on woody ornamentals can be found at this Link on pgs. 48-50

Reference:

https://www.fs.fed.us/rm/pubs/rmrs_gtr335.pdf

https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Peony%20Powdery%20Mildew.pdf

Powdery Mildew Resistant Peony Varieties

By Kenneth Dodson

Powdery Mildew is a common fungal disease that can appear on a wide range of plants. This year has seen a high level of powdery mildew on peonies, leaving bushes looking snow-covered or dusty. The best way to avoid dusty looking peony bushes is to use resistant plants. A look through the peony demonstration planting at the K-State Gardens showed a wide range of disease susceptibility to powdery mildew.

Pictured above: Powdery mildew on Peony (Paeonia spp.) 

Here are a few peony varieties that showed good resistance to powdery mildew. In terms of Herbaceous Peonies: Red Charm, Lillian Wild, and Pink Luau were the best options, followed by Madame de Verneville, and Pink Hawaiian Coral. If you’re looking for Tree Peony varieties, there are several that show strong resistance to powdery mildew: Rockii, Joseph Rock, Kamata Nishiki, Shima Daijin, Hakuo Jishi, Kinkaku, and Kokamon all looked good. Lastly, the Itoh or intersectional peonies Pea Green, Yellow Charm, and Morning Lilac exhibited good disease control against powdery mildew.

Just fyi, the major distinction between the three growing types is the in the way they overwinter. Tree peonies will have a woody stem that stays above ground, while herbaceous peony stems will die back to

the ground every year. Itoh varieties have herbaceous stems as well, and will die above ground, but Itoh peonies typically have the same flowering types as tree peonies.

Ash Leaf Spot on Green Ash Trees in Kansas

By: Christian Webb

You may notice brown spots beginning to develop on the lower foliage of green ash trees. Symptoms of Ash leaf spot include irregularly shaped brown spots on the leaf that merge to form large patches of brown spots. In severe cases, the tree may defoliate four to six weeks earlier than normal causing the tree to appear bare long before other trees lose their leaves.

Pictured above on the left: A branch of lower leaves on an Ash tree affected by leaf spot. Right: Brown leaf spots with white speckling on the surface of the upper leaf caused by Ash leaf spot

The fungi that cause Ash leaf spot (Mycosphaerella spp.) survive in the leaf litter underneath the ash tree. In the early summer, the fungi in the leaf litter will begin producing spores capable of infecting leaves. Initial infections will appear on the lower leaves, and then quickly spread throughout the tree. By late fall, the fungus will produce structures able to survive the harsh conditions of winter and be ready to infect new leaves during the following summer.

The severity of the disease will depend on the conditions present during the period of leaf infection. Typically, the disease will become apparent in the late summer and early fall, which may not cause significant cosmetic damage. But in summers with abnormally wet conditions, the disease may develop earlier than normal and cause premature defoliation. Multiple years of these conditions may lead to weak trees with reduced vigor prone to branch dieback.

Pictured above: A microscopic image of fungal structure emerging from the surface of the leaf.

There are few recommended methods to protect ash plantings from Ash leaf spot. Since the disease will survive in the residue around the trees, raking up fallen leaves will reduce the amount of disease carried over to the next growing season. No ash trees resistant to leaf spot have been reported although they may vary in susceptibility.

Reference:

More information on Ash leaf spot may be found at the following Link on page 46-47. https://www.fs.fed.us/rm/pubs/rmrs_gtr335.pdf

Turf disease update

(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

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

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.

Continued root and crown woes

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:

https://blogs.k-state.edu/turf/anthracnose-crown-rot-in-putting-greens-and-the-turf-stress-behind-it/

 

Localized dry spot

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.

Declining Oaks

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:

https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/oak-wilt.pdf

Common Oak Diseases in KS

  • Hypoxylon Canker
  • Bot Canker

Less common oak diseases in KS

  • Tubakia leaf spot
  • Bur oak blight
  • Oak wilt

Odd but interesting oak problems in KS

  • Oak galls
  • Obscure scale, Lecanium scale
  • Oak tatters

The rain didn’t stop us….Turfgrass Field Day 2019!

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:

  • Tree Pruning: Principles and Practices— Tim McDonnell taught about the different types, methods and reasons for tree pruning. Specifically, he demonstrated structural, raising and thinning practices, as well as making proper pruning cuts.

  • Ornamental Potpourri — Cheryl Boyer gave updates for ornamentals in Kansas, including the status of the John C. Pair Horticulture Research Center, popular new cultivars from local growers, an Earth-Kind Ninebark trial, and new Facebook marketing research results. She had a beautiful booth, full of luscious plants from KAT Wholesale Nurseries and Loma Vista Nursery.

  • New Tall Fescue Cultivars — Steve Keeley shared insights on a new tall fescue cultivar trial with over 130 entries that were established at Olathe in 2018. He showed the top performers and gave recommedations for tall fescue cultivars in Midwest lawns and sports turf.

  • Turf & Ornamental Insect Update —Raymond Cloyd shared an update on insect and mite pests of ornamentals and turfgrass, including new insecticides and miticidies, common insect and mite pests of 2019, and lots of “bug” samples.

  • Turf and Ornamental Disease Update—Megan Kennelly talked about diseases and stresses and how to identify and manage them. She also showed some tall fescue/zoysia blend plots and demonstrataed how the two species can complement each other.
  • Managing Shaded Turf —Dale Bremer talked about shade stress and how it affects turf performance, along with options to maintain turf quality in shade.

  • Turfgrass Weed Control Update — Jared Hoyle & Dani McFadden covered many aspects of turfrgass weed control advancements, including information about new herbicides, and how they influence your weed control program.

  • Advancements in Zoysiagrasss — Jack Fry showed of his “Innovation’ and ‘Chisholm’ turf plots – the new zoysias K-State has released. There are over 1,000 genetically different zoysias that are being evaluated at the Olathe Center.