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K-State Turf and Landscape Blog

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Turf disease update

Megan Kennelly, KSU Plant Pathology

Moisture and humidity are causing continued disease activity in both ornamentals and turf.

Below is some dollar spot activity in untreated controls in a fungicide study. As you can sort of tell from the photo, the disease has gotten to the point where the infection centers are not just off color but are also sunken/pitted.

If you are struggling with dollar spot control, consider your fertility regime. Low N can make the turf more susceptible, but high N comes with its own issues. Check your nozzles and spray equipment to ensure good coverage. Be sure to rotate among different modes of action. For more details check the dollar spot section starting on page 14 of THIS DOCUMENT.

 

We are getting some heat and humidity, and brown patch is becoming more active. Typically we think about brown patch as affecting tall fescue, perennial ryegrass, and our putting greens. However, this disease can affect bluegrass, too. This photo shows a sample from a Kentucky bluegrass fairway. You can see the fungal mycelium. With all the moisture, foliar Pythium also came to mind as a possibility, but in the microscope it was clearly the brown patch pathogen.

In the photo below, you can also discern that this is a heavy clay soil – see how shiny and glossy it looks. And, there is a thatch layer starting to build up, which can lead to its own set of problems. This site already has an aerification plan in place for fall.

 

The final disease I want to mention is Pythium root rot in putting greens.

Saturated soils alone can cause major decline in root systems. Unfortunately those same conditions can trigger Pythium root rot. The photos below illustrate typical symptoms I’ve seen recently, including several already this week:

When you pull up a turf core, the root system does not cling together well, and the whole core kind of lacks structure. If you wash them off, they are brown and mushy.

Canopy is thinned out and yellowing:

In the microscope the roots are dark, sloughing outer tissues, lacking root hairs, and have Pythium oospores present. (The physiological decline from wet soils alone can also cause browning, lack of root hairs, etc)

Here are a couple of resources about this disease:

https://turfpath.missouri.edu/profile/pythium_root_rot/index.cfm

and:

https://www.turffiles.ncsu.edu/diseases-in-turf/pythium-root-rot-in-turf/

National Pollinator Week!

Did you know it was National Pollinator Week?

In honor of National Pollinator Week, I wanted to share a video of bees pollinating on a Southern Magnolia tree that was located at the John C. Pair Horticultural Center in Haysville, KS. They caught my eye, as they were very “busy bees.”

Click on the link below to watch the video:

Video of Pollinating Bees

In addition to my short video, there is a wonderful video called “The Beauty of Pollination – Moving Art”. It is worthwhile to watch. Truly incredible!

For more information about National Pollinator Week, you can visit the official website. It’s not too late to celebrate. You can always plant a pollinator plant or take time for a garden walk to appreciate the pollinators in your garden.

Publication: Annual White Grubs in Turf

Dead spots in an otherwise healthy lawn may be a sign of white grubs. Grub damage varies from year to year and may be severe. The annual white grub is the most common grub pest of turf- grass in Kansas. It is the larval stage of the masked chafer beetle, Cyclocephala spp., which completes its life cycle in a single year. Six masked chafer species have been recorded in Kansas, all with similar developmental cycles: Cyclocephala lurida (southern masked chafer), C. borealis (northern masked chafer), C. pasadenae(southwestern masked chafer), C. hirta (western masked chafer), and Cyclocephala longula and C. melanocephala, which do not have common names.

To read this publication, visit this link to read it through the K-State Research and Extension bookstore.

Time to ‘Get Ready’ for Bagworms

By: Dr. Raymond Cloyd

For those of you that have been waiting patiently or for some… impatiently; it is time to ‘get ready’ to spray for bagworms. In due time, bagworms will be present throughout Kansas feeding on broadleaf and evergreen trees and shrubs. Therefore, now is the time to initiate action against bagworms once they are observed on plants. Bagworms are primarily a pest of conifers; however, they have expanded their host range to include a number of broadleaf plants, such as; rose, honeylocust, and flowering plum. It is important to apply insecticides when bagworms are small to maximize effectiveness and subsequently reduce plant damage.

To read additional information about this topic, continue reading this post that was featured in the KSU Extension Entomology Newsletter.

 

Removing Mosquito Habitats: Tips and Tricks

By: Brooke Garcia

You know it is spring or summer when the mosquitos are out for blood. However, they seem especially terrible this season, following a tremendous amount of rainfall in the NE Kansas area. It is difficult to enjoy our favorite activities outdoors when we are constantly being bitten. As an avid gardener, I have found it hard to withstand being outdoors for long periods of time. I’ve recognized the importance of implementing methods to suppress and eliminate mosquito habitats after a series of bites leaves me itching for revenge.

To overcome this 2019 mosquito battle, I wanted to provide you with some tips and tricks to reduce the mosquito populations surrounding your favorite places and spaces. For starters, eliminate pools of water in your garden. These can be found in planters, saucers, gutters, tires, tree holes, plastic covers, low spots, and/or any additional areas where water can be contained. As much as we enjoy our bird baths and water features, it is important to provide weekly maintenance to them. This includes emptying and changing out the water to remove potential mosquito habitats. If you happen to have a swimming pool, circulation of water and appropriate treatments are needed to eliminate mosquito habitats. In addition, avoid over-watering. As I was driving in Manhattan today, following a night of rain showers, I noticed someones sprinklers going off. The runoff and wet ground is only adding to this mosquito problem.

As far as chemical and/or organic methods of removal go, using appropriate barriers of protection against bites is highly advised. If you prefer not to use DEET, this is my go-to Insect Repellent recipe:

  • 1/2 cup water
  • 1/4 cup witch hazel
  • 45 drops of eucalyptus oil
  • 30 drops of lemon oil
  • 10 drops of peppermint oil
  • 6 ounce spray bottle

Be sure to shake well before applying often. Store this out of direct sunlight, and it should keep for 6-9 months.

Adding lemongrass and/or citronella into your planters or landscape are also advised as ways to reduce the mosquito population around your home.

Remember the structural barriers in which mosquitos can enter a building, home, or screened-in area. It is important to cover any holes or crack that may be found around windows and doors. If your screen door has a small hole in it, covering it with a piece of tape is a temporary fix until the screen can be replaced.

The overall goal is to avoid being bitten. It is our hope that these methods can easily be implemented into your life, or those surrounding you.

USGA: Improving The Cold Tolerance, Pest Resistance And Overall Quality Of Zoysiagrass

Post provided by USGA By Cole Thompson, assistant director, Green Section Research

Genetics ultimately determine how well grasses tolerate the stresses of golf as well as the most suitable playing surfaces and geographic regions for use. At times, management strategies may compensate for genetic shortcomings. For example, many cool-season grasses have excellent quality at very low cutting heights but require frequent irrigation and pesticide applications to mitigate damage from heat, drought or pests. Alternatively, some warm-season grasses tolerate drought and potential pests better than cool-season grasses, but may not provide the desired aesthetics or have the cold tolerance necessary to excel in colder regions. These compromises can make turfgrass selection challenging, especially in regions with diverse environmental conditions.

Because reliable turfgrass performance and resource efficiency are becoming more important to golf facilities, many are opting to use warm-season grasses and risking potential injury during harsh winters. In the case of ultradwarf bermudagrass putting greens, covering during low temperatures accounts for insufficient cold tolerance in the transition-zone region of the U.S.A. This is effective, but another strategy is to improve the genetics of warm-season grasses to diminish tradeoffs and reduce the resources required to deliver high-quality turf in a challenging environment.

Zoysiagrass is a warm-season grass that has already helped golf courses in the transition zone to use resources more efficiently. There are several species of zoysiagrass with different morphologies and cold tolerances. In general, zoysiagrass cultivars provide a high-quality playing surface with lower water, fertilizer and pesticide requirements than cool-season – and even some warm-season – grasses. The cold tolerance of Zoysia japonica cultivars – e.g., ‘Meyer’ – has made them ideal for fairways in the transition zone. To improve quality and further improve cold, shade and pest tolerances, the USGA has supported zoysiagrass development at Texas A&M University since 1983. The cultivars ‘Diamond’, ‘Cavalier’, ‘Crowne’ and ‘Palisades’ were developed and released from this support.

Since 2004, scientists at Texas A&M have partnered with colleagues at Kansas State University and Purdue University (since 2012). Initial success has come from crossing Zoysia japonica types with Zoysia matrella types, which have finer and denser leaves but less cold tolerance. ‘Innovation’ is a new cultivar released from these efforts, which has better quality and similar cold tolerance than ‘Meyer’ – the current standard-bearer for zoysiagrass in the transition zone. Since 2012, this group of scientists has worked to incorporate large patch disease resistance into their higher-quality, cold-tolerant zoysiagrass hybrids. They developed more than 2,800 new zoysiagrass hybrids and evaluated them in Dallas, Texas; Manhattan, Kansas; and West Lafayette, Indiana, from 2012 through 2014. The hunting billbug emerged as a problematic pest during this cycle of evaluation and hunting billbug resistance has since been a trait of interest. Researchers then selected the best 60 hybrid lines and evaluated them in 10 transition-zone locations from 2015 to 2018.

The 10 best hybrid lines have been advanced from the most recent evaluations for further testing. Large patch and hunting billbug resistance are improved in these lines when compared to ‘Meyer’, and some have better cold tolerance than ‘Meyer’. In 2018, the researchers began crossing these hybrid lines with lesser used zoysiagrass species such as Zoysia pacifica, Zoysia minima and Zoysia pauciflora, which have an even finer texture than Zoysia matrella types. Their ultimate goal is to produce zoysiagrass cultivars with all the aforementioned traits for fairways, tees and even putting greens.

*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.

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

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.