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K-State Turf and Landscape Blog

Category: Diseases

Spring turf diseases

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

As we move through spring and launch towards summer, don’t forget some key disease resources.

Fungicide info is available here:

https://entomology.ca.uky.edu/files/catmanualpdfs/ppa1.pdf

and here in a searchable online database:

https://turfpests.wisc.edu/filter.aspx?id=8-fungi

 

Large patch in zoysiagrass

Large patch has definitely been active lately with the cool, wet weather.

This is an area that was previously inoculated for a study, so it’s a high-pressure location:

In the photo below, the clear area was treated with a fungicide (tebuconazole) in early September and again in early October:

Some light N may help the turf recover. Some prior KSU work with U of Missouri (click here for info) and additional follow-up work by U of Missouri demonstrated that light N (think 0.25-0.5 lb/1000) in spring will not enhance this disease.

 

Dollar spot

 

 

The photo above is a worst-case scenario of the heaviest disease anywhere at Rocky Ford. It is an untreated area of a Cato-Crenshaw stand, which is highly susceptible. Untreated areas of less-susceptible cultivars are looking clean for now. KSU is part of a recently-published study that looked at disease susceptibility of various cultivars across several states. You can find a short preview/summary here.

What are you seeing? Let us know.

 

Root rot

We have not received samples here of Pythium root rot, but there are reports from nearby. You can read about findings of Pythium root rot in Missouri from our colleague Dr. Miller here:

https://turfpath.missouri.edu/reports/2019/05_14_19/

May Weekend Warrior Reminders

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

This time of year we can be caught of guard when it comes to maintaining our lawn.  Today we have some reminders about maintaining cool-season turfgrass for all you weekend warriors out there!

  • Reminder – Avoid frequent watering to reduce weeds germination and disease.
  • May is time for fertilizing cool-season turfgrass that is going to be irrigated. (See information below from Ward Upham.)
  • Mowing Tip – Only remove 1/3 of the leaf blade at a time and make sure you mow your lawn at the recommended mowing height. For more information on mowing your lawn – https://www.bookstore.ksre.ksu.edu/pubs/MF1155.pdf 
  • Mowing Tip #2 – Retuning your clippings to the lawn can return up to 25% of fertilizer nutrients that would be lost if clippings were to be removed. – https://www.bookstore.ksre.ksu.edu/pubs/MF2110.pdf

Fertilize Irrigated Cool-season Lawns in May By Ward Upham

May is an excellent time to fertilize cool-season lawns such as
tall fescue and Kentucky bluegrass if they will be irrigated throughout
the summer. Non-irrigated lawns often go through a period of summer
dormancy because of drought and do not need this fertilization.
May is a good time to fertilize because the springtime flush of
growth characteristic of these grasses has tapered off, so the
fertilizer you apply will be less likely to cause excessive shoot growth
than if you fertilized at a full rate in April. Slow-release nitrogen
sources are ideal. These nitrogen sources promote controlled growth,
which is desirable as the stressful summer weather approaches.
Relatively few fertilizers available to the homeowner supply ALL of the
nitrogen in the slowly available form. But one such product that is
widely available is Milorganite. Other such products available in the
retail market include cottonseed meal, alfalfa-based fertilizers, and
any other products derived from plants or animals. (Bloodmeal is an
exception, and contrary to popular belief, the nitrogen it supplies is
quickly available.) These products are all examples of natural organic
fertilizers. They typically contain less than 10 percent nitrogen by
weight, so compared to most synthetic fertilizers, more product must be
applied to get the same amount of nitrogen. Translation: they are more
expensive! Apply enough to give the lawn one pound of nitrogen per 1,000
square feet. For example, if the fertilizer is 6 percent nitrogen by
weight, you will need to apply almost 17 pounds of fertilizer product
per 1,000 square feet. Summer lawn fertilizers that contain at least a
portion of the nitrogen as slow-release are fine to use as well. Be sure
to follow label directions. If cost is prohibitive, you can use the less
expensive quick-release (i.e., soluble) sources, but split the
application into two doses as follows: apply enough to give the lawn 0.5
lb nitrogen per 1,000 square feet in May and again in early June.

***** Reminder –  These are recommendations for cool-season turfgrass species!*****

For more information on tall fescue lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=1460

For more information on Kentucky bluegrass lawns – https://www.bookstore.ksre.ksu.edu/Item.aspx?catId=545&pubId=816 

Cedar apple rust

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

The birds are singing, the tulips are blooming, and junipers (also called red cedars) are “blooming” in another fashion.  Cedar apple rust is here.  The pathogen (a fungus) spends part of its life cycle on a juniper tree, and the other part of its life cycle on apples, crabapples, hawthorns, or quince.  To simplify, we’ll just call them “apple hosts.”


Those jelly-like orange masses on the junipers produce spores that infect the apple hosts.  Once infection occurs, leaf spots on apple leaves develop in 1-3 weeks.  Eventually, fungal spores are produced in these leaf spots on the apple tissues.  The spores are spread by wind and rain back to junipers starting in about July.  Without both hosts, the fungus can’t complete its life cycle.
The disease looks dramatic on junipers, but it does not cause any harm.  The rusts can cause problems in the apple host, however.  If infection is severe, many leaves drop off early and the tree is weakened due to reduced photosynthesis.   If your tree only gets a small amount of rust each year, it probably won’t be an issue for long term tree health.
Management options (for apple hosts):
1) Resistance:  For new plantings of fruiting or flowering apples, consider planting a rust-resistant variety.  Information on crabapple cultivars is available at:

https://bookstore.ksre.ksu.edu/pubs/MF875.pdf

2) Tree care:  For any apple tree, proper pruning will allow air movement through the canopy. This practice reduces the leaf wetness that promotes disease.  Maintaining overall tree health will also help prevent the disease.
3) Fungicides:  Homeowners with a bad history of this disease (severe defoliation), might consider preventative fungicide sprays on the apple hosts when leaves are out and the orange galls are active.  For best control, applications should continue through May or as long as the orange galls are active. Products with the active ingredients myclobutanil or propiconazole are examples of materials labeled for cedar apple rust management in flowering crabapples and non-fruiting apples.  Make sure you check the label carefully. For example, if you are talking about fruiting apples instead of flowering crabapples, some products are not allowed.

Commercial fruit growers should consult the Midwest Fruit Pest Management guide: https://ag.purdue.edu/hla/hort/documents/id-465.pdf

There is also a video on rust diseases at: https://www.youtube.com/watch?v=yQdwSPtvhH8  The video is 15 minutes long and describes the life cycle and biology of these fascinating fungi!

Paying Attention to Pine Diseases

Posted on by Brooke Garcia

Now is a really good time to check for Dothistroma Needle Blight on Austrian, Ponderosa and Mugo pine trees. Several pine samples from northeast Kansas have the K-State Plant Disease Diagnostic Lab with classic symptoms. This disease tends to show up in crowded, mature pine plantings. The key is crowded plantings that lead to poor air circulation. Wet weather and poor air circulation lead to increased disease severity.

    

If you are trying to sort out winter damage from Dothistroma needle blight, the first thing to do is to look into the bottom of the tree. Dothistroma causes needle shedding and tends to be more severe in the bottom of the tree. Essentially when you look into the bottom of the tree, the interior needles are gone and all of the lower limbs tend to be bare. Needle loss tends to be particularly severe in crowded windbreaks where air circulation is poor.

Next take a look at the foliage. The needles will have scattered spotting and a half needle scorch. The outer needle tip will be brown and the inner portion of the needle will be green. Each needle will be affected in a different location.

You can contrast this with winter burn which can also produce a half needle scorch but will always burn all of the needles back in exactly the same location. Plus the damage tends to be in the outermost foliage.

The last thing to look for is raised black fruiting bodies (acervuli) on the affected needles. This is diagnostic sign for the disease. You may need a magnifying glass or 10X hand lens to see them, although when they are fully mature they are visible with the naked eye. The fungal fruiting bodies don’t start developing until late December or January, but now is a good time to look for them. If you don’t initially see them you can put the suspect needles in a Ziploc bag with a wet paper towel for couple of days. The high humidity will help the fruiting bodies pop out.

Dothistroma needle blight and winter damage can look very similar. If you are going to spend money to treat for the Dothistroma needle blight disease then it is a good idea to confirm that the disease is present. Samples can also be sent to the K-State Plant Disease Diagnostic Lab at the address listed at the bottom of this post. Dothistroma needle blight can be managed with fungicides.

For more information on managing this problem see the pine disease factsheet at the following web link (O’Mara):

https://www.bookstore.ksre.ksu.edu/pubs/l722.pdf

K-State Plant Disease Diagnostic Lab
4032 Throckmorton, PCS
1712 Claflin Rd
Manhattan, KS 66503
Send Questions to: jomara@ksu.edu
Testing for Needle Blight: $10 Extension/$13.50 Non-Extension

Cut and destroy those pine wilt infected trees ASAP

Posted on by kennelly

(Megan Kennelly, KSU Plant Pathology)

Pine wilt has been killing our pines for decades. It is caused by a nematode (microscopic worm) that is spread by a beetle. The nematodes and beetles spend the winter in dead and dying trees. The beetles, loaded up with nematodes, start emerging in late April or early May and spread to new trees. Got pine wilt? Get that tree outta there! Chop it down, and burn or chip the wood, making sure not to leave stumps. Get this done in early April to stop disease spread.

If you have a dead pine in the eastern 2/3 of Kansas it could very well be pine wilt. Sure, it could be something else, like drought, but if it’s dead anyway you might as well assume it is pine wilt, and get it out and destroyed. You can send a sample in to KSU for testing if you want to know.

And, if you suspect pine wilt in the western part of the state, contact your local county K-State Research and Extension agent for help. Not only do we want it destroyed, we want to know where it is so we can understand where disease is spreading. (Find your agent here: https://www.ksre.k-state.edu/about/stateandareamaps.html)

 

Entirely dead tree? Cut it down and destroy the wood by chipping or burning.

 

 

 

Pines have multiple problems though, such as tip blight and Dothistroma needle blight. If you have any doubt you can work with your KSRE Extension agent to ship a sample up to KSU. For more information on pine diseases, and how to tell them apart, check out our publication about Pine Diseases in Kansas

Weekend Warrior Turfgrass Lawn Care

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Finally I think we have turned the corner into Spring.  With that, I see more and more of my neighbors, and myself, working in the yard.  I get excited when the turf starts to turn green.  But before I get too carried away I want to get out on the right foot and planning is everything.  To help help you plan out your lawncare program below are monthly calendars for tall fescue, Kentucky bluegrass, buffalograss, bermudagrass and zoysiagrass.

Bermudagrass and Zoysiagrass Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-guide-to-bermudagrass-and-zoysiagrass-lawns/

Buffalograss Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-buffalograss-lawn-guide/

Tall Fescue and Kentucky Bluegrass Lawns

https://blogs.k-state.edu/turf/a-homeowner-step-by-step-tall-fescue-and-kentucky-bluegrass-lawn-guide/

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

K-State Radio Network “Plantorama” – Home Lawn Winterkill

Posted on by jahoyle

(By Jared Hoyle, KSU Turfgrass Research and Extension)

HOME LAWN WINTERKILL– It was a fairly harsh winter in this region.  And that has homeowners wondering if their lawn grasses were adversely affected by the extended cold and wet conditions. K-State turfgrass specialist Jared Hoyle says while the likelihood of outright turfgrass winterkill is relatively low, some limited damage may have occurred.

Click the link below for K-State Research and Extension Agriculture Today Radio Program “Plantorama” hosted by Eric Atkinson.

Check out the KSRE bookstore more more information on all things turf! – https://www.bookstore.ksre.ksu.edu/Category.aspx?id=528&catId=545

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

Control of Turfgrass Diseases

Posted on by jahoyle

“Turfgrasses under intensive management are often subject to outbreaks of infectious diseases. Diseases usually are most damaging when weather or cultural conditions favor the disease-causing agent but not plant growth and vigor.”

http://www2.ca.uky.edu/agcomm/pubs/PPA/PPA1/PPA1.pdf

This quote from the “Chemical Control  of Turfgrass Diseases 2017” publication at University of Kentucky and Rutgers University, really sums up why we have diseases in our turfgrass systems.  Many times we have no control over weather or the cultural conditions that favor disease-casuing agents and those same conditions do not favor turfgrass growth.  To prepare for 2019 download this publication from Drs. Vincelli, Clark and Munshaw and keep it around as a great reference.  I keep a copy of this publication along with my weed control manual (https://blogs.k-state.edu/turf/new-turfgrass-weed-control-for-professionals-2019/) at all times.

  • Jared Hoyle

First 2019 Disease Report from Mizzou

Posted on by jahoyle

Only of our good friends to the east, Dr. Lee Miller, posted his first disease report of 2019.  In this update he covers what we have been through over the past winter and what to look for in the weather to come.  Check it out!  This is some great information, especially if you are on the east side of Kansas.

https://turfpath.missouri.edu/reports/2019/update03_21_19.cfm?fbclid=IwAR2-mfRuh5r_-pnd8LbpHYEPEsZn4z2-pOwpE77hr6ozxUS4aVW1MHblfso

(Figured I would add a picture in here that shows some green turf! – Jared Hoyle)

Large patch in research plots

Posted on by kennelly

Before the snow hit I was able to view some large patch symptoms in our breeding plots with our PhD student Manoj Chhetri.

Strong large patch symptoms:

Not much symptoms here:

Definitely some differences in % green after the recent cold snaps, but before the snow and this weeks extreme cold temps: