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*SPECIAL ALERT* Sudden oak death pathogen reported in Kansas

Megan Kennelly, KSU Plant Pathology

The Kansas Department of Agriculture confirmed the presence of Sudden Oak Death (SOD) in Kansas. The KDA press release from today can be found here:

https://agriculture.ks.gov/news-events/news-releases/2019/06/07/plant-disease-identified-in-rhododendrons-in-kansas

SOD is a plant disease that has killed large tracts of oaks and other native species in California and Oregon. It also occurs on nursery plants including  rhododendron, azalea, camellia, viburnum, lilac, and periwinkle. Infected rhododendrons have been identified in 10 states in the Midwest, including Kansas. The infected plants that have been found in the Midwest have all been traced back to a common source.

This is a serious situation, and we ask that if you have purchased, planted, or maintained rhododendrons or other known host plants this spring please read the  information on the provided links and documents below and take action as needed.

Many details and photos are provided on the KDA website:

https://www.agriculture.ks.gov/SOD

We have provided some additional details in a pdf that you can access by clicking the link below:

KS SOD FAQs_2019

KDA, K-State, and the Kansas Forest Service are all working collaboratively to address this situation.

K-State’s press release from today is here:

https://www.ksre.k-state.edu/news/stories/2019/06/Sudden-Oak-Death-Reported-in-Kansas.html

If you have questions, you can email me at kennelly@ksu.edu (or call 785-532-1387) or Cheryl Boyer (KSU nursery crops specialist) at crboyer@ksu.edu (785-532-3504).

 

Spring Brings a Little Bit of Everything

By Judy O’Mara

Take Closer Look at the Roses

The cool, wet spring weather is amazing for rose shrubs. They are blooming like crazy. However…if you take a closer look, you might notice that the blooms don’t last that long. They seem to fall apart and drop their petals very quickly. This is one of those instances where there actually is a disease involved. A fungal disease called Botrytis blight can cause tiny spots on the flower petals. If conditions are favorable (cool, high humidity, wet), then the blooms can look like they have the measles. Infected blooms quickly fell apart. The problem self corrects itself when the temperature increases and the weather dries out.

Fungi just Love Mulch

I planted some flowers and mulched the flower bed this weekend. When I opened the bag about twenty percent of the mulch had a white fungal mold. Questions about this issue turn up every spring. Basically mulch molds are wood decomposers. They occur as part of the natural ecosystem that breaks down organic matter. This is probably why we have to replace the mulch in our flower beds every year.

What triggers the prolific growth is a combination of wet conditions and large amounts of organic matter. Very likely the bag had a hole in it and water got inside.

Heavy amounts of mold can create a hydrophobic zone which can prevent water from getting to the plant roots. This can be avoided by breaking up the fungal mass.

It is not necessary to use fungicides to get rid of them. They are pretty much present whether we see them or not.

Another interesting mulch problem is Dog Vomit aka Slime mold. 

Slime molds start out as a colorful, slimy mass that dries down to a powdery material. They are common in mulch or turf. They can even crawl up on lawn furniture. They are favored by cool, wet conditions and are easily knocked back with a stream of water from a hose or even a rake.

For more information on this interesting phenomenon check out this web site at the Utah State University Herbarium. https://herbarium.usu.edu/fun-with-fungi/slime-molds

Diplodia tip blight

Across the state of Kansas, the most common pine disease is Diplodia tip blight (aka Sphaeropsis tip blight). The disease attacks the new shoot growth as it emerges in the spring. About the end of May, new shoots visibly die back on the ends of the branches. Over time, the disease can develop as a canker further back and result in a die back of the entire branch.

This fungal disease is primarily a problem on mature pine plantings (ie crowded, with poor air flow). Over a period of many years (10-15), the disease slowly chews up the tree resulting in a tree that appears half dead. The black pepper speck, fungal fruiting bodies (pycnidia) on the back of the pine cone scales are a key diagnostic feature for Diplodia tip blight.

Those are the facts, so…I was taken back by two separate pine samples that came through the K-State Plant Disease Diagnostic lab last week. Both pines had Diplodia tip blight, causing a shoot blight of the new growth, but…they were from young trees (3-5yrs old)!

However…on one sample the new trees were planted next to a line of older pine trees, which was probably the source of the disease inoculum.

Bentgrass Putting Green Fertility – Helping or hurting silvery-thread moss?

(By Jared Hoyle, KSU Turfgrass Research and Extension)

At Rocky Ford Turfgrass Research Center in Manhattan, KS we have two bentgrass putting greens.  On one of them we “try” to maintain as a common putting green with typical disease, weed and fertility programs.  On the other one we don’t apply any fungicides at all to see what disease we can grow.  On that same putting green we are growing a nice crop of silvery-thread moss as we aren’t doing anything to help suppress or control it.

When I came on board here at KSU in 2013, the KSU Turfgrass Faculty and graduate students were really diving into figuring out programs to help control or suppress silvery-thread moss in bentgrass putting greens.  Quick to find out, controlling moss is not just an application but a program and part of that program is fertility.

I quickly went through some of the past research reports on the KSU Turfgrass Website (https://www.k-state.edu/turf/research/index.html) and came across a short report on the influence of nitrogen source and spray volume on the establishment of silvery-thread moss.  Establishment! Establishment!  Why are we studying the establishment?  Well, knowing what helps establishment also tells you what is going to promote growth of silvery-thread moss.

As Drs. Raudenbush and Keeley explain in the research report, “the practice of spraying small quantities of soluble nitrogen at a relatively high frequency my promote silvery-thread moss growth because the moss lacks a vascular system of removing water and nutrients from the soil.”  Apply small quantities of soluble nitrogen at relative high frequencies is a common practice for managing bentgrass putting greens, so we maybe making the problem worse.

To summarize the project that was conducted in the greenhouse, spraying soluble nitrogen increased moss cover compared with the untreated control and ammonium sulfate has the highest moss cover at all the ratings dates.  Comparing ammonium sulfate to urea, ammonium sulfate caused more than a threefold increase in moss dry weight (At 7 weeks after the initial treatment the moss was harvested, dried and weighed.) and there was no difference between urea and the water only control.

There are many other factors to consider when looking at suppressing or controlling silvery-thread moss including but not limited to; watering, herbicide applications, topdressing and promoting healthy bentgrass. But remember fertility, as it does play a roll in silvery-thread moss management.

For the full report check out Page 12 of the 2014 Kansas State University Turfgrass Research Report – https://krex.k-state.edu/dspace/bitstream/handle/2097/20427/Turfgrass2014.pdf?sequence=1&isAllowed=y

Should we be hitting the panic button on goosegrass control?

(By Jared Hoyle, KSU Turfgrass Research and Extension)

Not too long ago I received a text from a friend of mine with a picture of goosegrass and the caption, “goosegrass emergence reported in Salina, KS in areas w/o PRE.”  With the mild temperatures and just now seeing crabgrass germinate in some thin areas where no preemergence has been applied, I thought to my self, “Oh no.”  I then posted the picture on Twitter to let everyone know what was going on in the area.

One of my good friends, Scott, down in Georgia commented “Should we hit the panic button?”

To answer that question honestly… I’m not sure.  Then I went back and looked at the picture.  There was a set of keys in the picture to help show the relative size of the goosegrass and on the key was a “panic” button that is commonly on keyless entry vehicles. Ironic?

So should we hit the panic button?  I am not sure but I do think that means we need to keep an eye out and know that goosegrass is on its way if not already germinated and especially in areas that haven’t been applied with a preemergent herbicde.

Goosegrass (Eleusine indica) is a summer annual weed that typically germinates after crabgrass in the spring.  That is about when the soil temperatures consistently reach approximately 60° F.  Like crabgrass, goosegrass is best controlled with a preemergence herbicide.   Herbicides that contain the active ingredient oxadiazon work very well.  Other preemergence herbicide efficacy can vary.

But as it seems like everyone has already put down preemergence herbicide so, you have nothing to worry about.  Well what if you didn’t, or there is break through?  There are some POST application control options.

First, Know you turfgrass species.  Your herbicide selection is going to vary greatly depending on species.

If you have cool-season turfgrass then you can use fenoxaprop (Acclaim Extra), fluazifop (Fusilade II), tropramizone (Pylex), or MSMA (golf courses and sod farms only!).  You will probably have to do more than one application if the goosegrass is tillered out.  Sulfentrazone (Dismiss) is also effective on goosegrass if it has not tillered out yet.

Bleaching of goosegrass from topramazone application

Creeping Bentgrass

For all you golf courses out there that have creeping bentgrass fairways it is going to be a little bit more difficult because the herbicides that work best tend to injure  the turf.  1-Tiller or smaller can be controlled with fenoxaprop (Acclaim Extra) at 3.5 fl oz/A but you will need to re-apply every two weeks to make sure you are applying to small plants.

As crazy as it sounds a herbicide that has commonly been used for broadleaf weeds has shown control on goosegrass.  SpeedZone (2,4-D +dicamba + MCPP) has shown control but a follow up[ application is going to be needed 30 days after initial application.

Tropramizone (Pylex) can be used on bentgrass at lower rates (0.25 fl oz/A) but definitely might need a repeat application at 21 days

Bermudagrass and Zoysiagrass

Now if you have bermudagrass or zoysiagrass then you can use Tribute TOTAL (thiencarbazone + foramsulfuron + halosulfuron).  Fusilade II and Acclaim Extra that works in cool-season grass can also be used on zoysiagrass.  If you mix these products with triclopyr (Turflon Ester Ultra or Triclopyr 4) then you will get better results.

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

Save the Date: Kansas Turf & Ornamentals Field Day – August 1st, 2019

The Kansas Turf & Ornamentals Field Day will be held on Thursday, August
1st at the K-State Research & Extension Center in Olathe (35230 W. 135th St.).

The field day program is designed for all segments of the turf & ornamentals industry – lawn care, athletic fields, golf courses, nursery, landscape & grounds maintenance. Included in the field day program: research presentations, problem diagnosis, commercial exhibitors, and equipment displays.

 

There will be time to see current research, talk to the experts and get answers to our questions.

One hour of pesticide recertification credit in both 3A & 3B is available, as well as GCSAA education points.

For more information, go to: https://www.k-state.edu/turf/events/index.html

Got Thatch?

By: Ward Upham

Thatch Control in Warm-Season Lawns

Thatch control for cool-season lawn grasses such as bluegrass and tall fescue is usually done in the fall but now is the time we should perform this operation for warm-season turfgrasses such as bermudagrass and zoysiagrass. Because these operations thin the lawn, they should be performed when the lawn is in the best position to recover. For warm-season grasses that time is June through July. Buffalograss, our other common warm-season grass, normally does not need to be dethatched.

When thatch is less than one-half inch thick, there is little cause for concern; on the contrary, it may provide some protection to the crown (growing point) of the turfgrass. However, when thatch exceeds one-half inch in thickness, the lawn may start to deteriorate. Thatch is best kept in check by power-raking and/or core-aerating. If thatch is more than 3/4 inch thick, the lawn should be power-raked. Set the blades just deep enough to pull out the thatch. The lawn can be severely damaged by power-raking too deeply. In some cases, it may be easier to use a sod cutter to remove the existing sod and start over with seed, sprigs or plugs.

If thatch is between one-half and a 3/4- inch, thick, core-aeration is a better choice. The soil-moisture level is important to do a good job of core-aerating. It should be neither too wet nor too dry, and the soil should crumble fairly easily when worked between your fingers. Go over the lawn enough times so that the aeration holes are about 2 inches apart.

Excessive thatch accumulation can be prevented by not over-fertilizing with nitrogen. Frequent, light watering also encourages thatch. Water only when needed, and attempt to wet the entire root zone of the turf with each irrigation.

Finally, where thatch is excessive, control should be viewed as a long-term, integrated process (i.e., to include proper mowing, watering, and fertilizing) rather than a one-shot cure. One power-raking or core-aeration will seldom solve the problem.

What’s What on Juniper Shrubs?

By: Judy O’Mara

You can drive to any grocery store, fast food restaurant or mall in Kansas and see a spreading juniper shrub planting. They are pretty well adapted to Kansas but a few problems show up.

Winter damage is common following cold temperatures and desiccating winter winds. Die back tends to show up on the ends of the branches during December through February. If the damage isn’t too bad, it can be pruned out and with some added care, the shrubs may recover.

Snowy and Salty

In addition to cold temps last winter, there was lots of snow. According to Assistant State Climatologist, Mary Knapp, Manhattan Kansas received 27.8” of snow during the recent winter, which is 11.1” over the normal 16.7” snowfall. So what does this have to do with junipers? Well, with snow comes slippery sidewalks and driveways, which in turn can lead to the use of salt or de-icing products. They work pretty well to keep people safe slipping and breaking a hip, but sometimes the products can damage nearby shrubs.

It is not uncommon to see salt damage or browning on the side of juniper shrubs closest to the sidewalk in the spring. In this case, salt leached from the sidewalk and burned the roots closest to the edge. There is a nice article on which ice melts are appropriate to use at the K-State Johnson County Extension web site. Something to keep in mind for next winter.

Pictured above on the left, the juniper shrubs are experiencing salt burn from the sidewalk. Pictured above on the right is a heavy concentration of salt crystals.

Wet and More Wet

I got caught in a down pour on a recent trip to Hiawatha, KS.  The area creeks were flooded and topped the roads in a few places. It was an awesome sight, plus a little bit scary. It’s been a fairly common phenomenon this spring and there are a number of articles out there on the impact of flooding on landscape plants. I thought I would throw in my two cents, as well.

One of the more serious challenges for junipers plantings is damage due to ‘wet feet’. It is not uncommon during heavy spring storms to see shrubs floating in a pool of water. Aggravating factors may be locations with heavy clay soils that drain poorly or even locations that have a compaction layer not far from the soil surface. In either case, prolonged expose to wet soils will damage the roots and cause a collapse of the planting. I tend to think of this as center decline. Sometimes the entire plant will die, and sometimes just a portion (frequently the center). So, if a large section of the planting is going out, it may be a root health issue. Juniper shrubs never recover from this type of damage. It is really important to select a well-drained site for juniper plantings.

Branch Tip Die Back

I know this juniper shrub looks bad but, it’s actually okay. The damage here is caused by a fungal disease called Kabatina tip blight. It causes a die back of the branch tips, usually 2-8” with symptoms showing up between February and mid-June. It can cause a scattered branch die back or it can hit every single tip, making the shrub look like it is going to die. But no, like magic the planting recovers. By late June, the dead tips dry up and fall, slowly improving the appearance of the shrub. Some creeping junipers are particularly susceptible.

As always, there is the question ‘What can I spray?’. There are two reasons why that is not a practical option. One, the infection period is in the fall, so by the time you see the symptoms it  is too late to spray. Two, the disease is basically a cosmetic issue. In most years, it shows up as scattered dead tips (barely noticeable). In years with a prolonged cool, wet spring Kabatina tip blight symptoms can be dramatic. But…summer eventually arrives and with warmer temps and drier conditions disease activity halts. At that point, the dead tips start dropping off and the planting starts to look better. So best management option? Do nothing, or maybe rip it out and plant something less susceptible.

Pictured above, you can see daffodils, so you know it is early spring and conditions are favorable for Kabatina tip blight. Pictured on the right is the same planting later in the season. As you can see, all of the dead tips have dropped off of the plant.

 

Spring Leaf Drop – Sycamore Anthracnose

by Judy O’Mara

I walk past a big beautiful Sycamore tree on my way into work every day. I recently noticed leaves dropping to the ground. A close look at the defoliated leaves showed the characteristic symptoms for a fungal disease called sycamore anthracnose – brown lesions along the veins and on the petiole. Once the water conducting tissue in the veins is damaged, the leaf gets knocked off the tree. Also visible in the tree were also small, blighted shoots.

Sycamore anthracnose is a spring disease, meaning it is favored by cool (60-73F), wet conditions. With a prolonged spring weather pattern, the disease can sometimes look dramatic. In Kansas, chemical control of this disease isn’t necessary. With the move into warmer summer weather, sycamore anthracnose ceases activity and the tree pushes out a new flush of growth.

Sandbur Control for Turfgrass Professionals

Photo credit – https://hnr.k-state.edu/extension/info-center/common-pest-problems/common-pest-problem-new/Grassy%20Sandbur.pdf

(By Jared Hoyle, KSU Turfgrass Research and Extension)

It is that time of year where we are going to start seeing more and more summer annual grassy weeds emerge, especially if you didn’t get a preemergent herbicide down.  One of that problematic summer annual weeds is sandbur (Longspine sandbar – Cenchrus longispinus; field sandbar – Cenchrus incertus).  These sandbur species are often found in sandy soils but can grow in a wide range of soil conditions.  They can appear to look like crabgrass and foxtail but the seedheads are spike-like racemes with bur-like fruit.  This is the major problem.  These seedheads can cause physical injury to a person, animals and equipment.

There is good news.  Like many of the other summer annual weeds you can control sandbar with preemerge herbicides if you follow the recommendations for preemergent crabgrass control.

But if you have an escape or didn’t treat with a preemerge herbicide this year you have a couple of options;

  • Herbicides that contain fenoxaprop (Acclaim Extra, Last Call), MSMA or topramazone (Pylex) are most effective (≥ 90% control).
  • To achieve 75-90% control use; asulam (Asulox), fluazifop (Fusillade II, Ornamec), imazapic (Plateau), sethoxydim (Segment II) and sulfentrazone + imazethapyr (Dismiss South).
  • Atrazine (AAtrex) and simazine (Princep) provide fair control (50-75%)
  • The flowing herbicides have resutled in some activitly but ≤50% control.
    • 2,4-D+quinclorac+dicamba (Momentum Q, Quincept)
    • carfentrazone+2,4-D+MCPP+dicamba (Speedzone)
    • ethofumesate (Prograss)
    • foramsulfuron (Revolver)
    • imazaquin (Image 70DG)
    • mesotrione (Tenacity)
    • metsulfuron (Manor, Mansion)
    • metsulfuron + rimsulfuron (Negate 37WG)
    • pronamide + quinclorac (Cavalcade PQ)
    • pronamide (Kerb)
    • quinclorac (Drive XLR8)
    • quinclorac + sulfentrazone +2,4-D + dicamba (Q4 Plus)
    • sulfentrazone (Dismiss)
    • sulfentrazone + quinclorac (Solitare)
    • trifloxysulfuron (Monument)

For more information on sandbur and many other weeds, check out Turfgrass Weed Control for Professionals 2019 Edition – 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

 

Little Barley Control Options (or Option)

(By Jared Hoyle, KSU Turfgrass Research and Extension)

I was walking through some of our research plots (with waders on due to all the rain) and I came to a nice patch of little barley.  It was lush!  I thought to myself, “How did this get so bad?” but, then I noticed there wasn’t any turf in the area at all.  Little barley (Hordeum pusillum) is a winter annual that is many times confused with foxtails because the seedbed look similar. To see the differences in seedbeds click here –  https://blogs.k-state.edu/turf/tag/little-barley/

But the problem is I have lots of little barley and what do I do;

1.Promote healthy dense stand of turfgrass. Maybe overseed this spring/early summer if you have to depending on your situation and turfgrass species. Definitely overseed in the fall if you have cool-season turfgrass.

2. Use a preemergence in the fall.

3. Can use Certainty (sulfosulfuron) in warm season turfgrass but typically don’t.

4. Do nothing….  Seems like a trick question but this species will thin and die as temperature increase in the summer.

So there are a couple of options but if you do have little barley it is probably because the turfgrass isn’t doing well.

For more information on little barley and many other weeds, check out Turfgrass Weed Control for Professionals 2019 Edition – 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