Bermudagrass Greens Looking Bad?

Recent weather patterns of cool/cloudy/rainy weather across much of North Carolina have been perfect for foliar diseases such as Bipolaris leaf spot and Pythium blight on bermudagrass putting greens.

Bipolaris Leaf Spot Symptoms on Ultradwarf Bermudagrass

We have received many samples in the past week at the NC State Turf Diagnostics Lab that were devastated by the fungus Bipolaris cynodontis. Bipolaris leaf spot is most severe on turf that is growing slowly due to adverse weather conditions or improper management practices.  Shaded areas with little or no air movement result in weak turf and extended periods of leaf wetness that favor disease development. Deficient or excessive nitrogen, excessive thatch, extended periods of leaf wetness, and low mowing heights are factors that encourage the development of leaf spot diseases. The fungus is easily spread by mowers, wind, and/or rain.

For more information about Bipolaris leaf spot, including control recommendations, click here.

Ultradwarf Bermudagrass Devastated by Pythium Blight
(note mycelium on leading edge)

We have also diagnosed many bermudagrass samples this week with Pythium blight in conjunction with leaf spot or acting alone. The symptoms are a rapid foliar blight that initially has a purple coloration but then fades to tan. Spreading by mowers or in drainage patterns usually occurs as well. 

Pythium blight in October? Yes, you read it correctly, it is Pythium blight in October. There are a lot of Pythium species that can infect grasses. Most people are familiar with P. aphanidermatum that causes Pythium blight on the cool season grasses during hot summer weather. However, there are other Pythium species that grow during cool or cold weather. We don't know what species is causing this outbreak yet, but obviously it grows well during cool weather and has a competitive advantage over the bermudagrass under these conditions.

Fungicide treatments may not always be necessary to control Pythium blight on bermudagrass, as dry and sunny weather usually put a stop to it very quickly. However, if the forecast is calling for extended periods of wet and cloudy weather, an application might be a good idea. Any strong Pythium fungicide should do a good job.

What's Happening Now?

RECENT CREEPING BENTGRASS PROBLEMS

Over the past several weeks, we have received many creeping bentgrass putting green samples.  In every case, samples were submitted to check for a disease and in EACH case absolutely no pathogen activity was discovered.  Therefore, our diagnosis was "a disease was not responsible for the damage".  The common thread has been the combination of core aerification and topdressing with the unusually arid weather for this time of year. When the putting surfaces are opened up after aerification, they are more susceptible to drought stress, especially if the humidity is very low. This effect is exacerbated in areas that are already stressed such as clean up laps, heavy on/off traffic spots, etc.

This is a fine example of why receiving a diagnosis of "no disease" is just as important as receiving a diagnosis of an actual disease. Because symptoms developed during excellent growing conditions for creeping bentgrass, a safe assumption is a disease is responsible for the damage.  Yet, in this case an accurate diagnosis can save time and money by preventing unwarranted fungicide applications.  If you don't agree, feel free to make a fungicide application for drought stress and see what happens.

Typical Stress Symptoms Observed with Recent Samples

TREAT FOR LARGE PATCH NOW!

With soil temperatures starting to approach 70°F across portions of NC, now is the time to treat for large patch.

Average Daily Soil Temperatures as of 10/01/13 via NC State Climate Office

Large patch, which is caused by the fungus Rhizoctonia solani, is a common disease of centipedegrass, St. Augustinegrass, zoysiagrass, and bermudagrass grown for lawns, landscapes, golf turf, and athletic fields. Centipedegrass and St. Augustinegrass are particularly susceptible to severe damage from this disease.

Symptoms of large patch appear in roughly circular patches from 2 feet up to 10 feet or more in diameter. The affected turf will initially be orange, yellow, or reddish-brown in color but will then turn tan and collapse to the ground. The disease can spread rapidly to encompass large areas of turf, and distinct circular patches may not be obvious in these cases.

Fungicides are available for large patch control, but they must be applied preventatively for best results. The first application should be made in the late summer or early fall when average daily soil temperatures are 70°F or below.

One fungicide application will control minor cases of large patch, but two to three applications on a 4 to 6 week interval may be needed to control severe cases. Fungicides are not very effective once the symptoms of large patch appear. Curative applications will help to reduce further spread of the disease, but the affected turf will be very slow to recover.

For more information about Large Patch, including images and specific control recommendations, click here.


TREAT FOR SPRING DEAD SPOT NOW

So, your first question may be "Why on Earth are you telling me to apply fungicides for a spring disease in the fall and for something that will not show up for another 6-7 months?!"  The answer is simple.  The causal fungus, Ophiosphaerella spp., is active RIGHT NOW and you can bet it's infecting your bermuda and zoysia grass plants as I type this blog.  We know through years of research that fungicides are most effective when the soil temperatures are between  60 - 80°F in the fall of the year.

Choosing the right fungicide and applying at the right time will not result in acceptable levels of control if you do not apply them correctly.  Spring dead spot infects below ground plant parts.  With that being said, you must either water-in your fungicide applications IMMEDIATELY  with 1/4" of irrigation or apply with a carrier volume of 5 gal/water/1,000 sq. ft.  You need to be running your irrigation the moment the applicator is out of the way.  Do not wait until the following evening or night with your routine irrigation schedule or else you may be severely disappointed come next spring when these grasses green back up.

Just recently we have made some fantastic discoveries with fertilizers in regards to controlling this disease without having to use fungicides at all!  To learn more about this, please click here.

To learn much more about spring dead spot, including control recommendations, please click here.

Now Accepting Credit Cards!

We have finally joined the rest of the world in the 21st century and can accept Master Card or Visa for services rendered through the NC State Turf Diagnostics Lab.

If you currently have an outstanding invoice with us, you can contact me via email and I will send you the payment link.

If anyone has any questions about this new option, please contact me.

Lee Butler
NC State Turf Diagnostics Lab
(919) 513-3878
lee_butler@ncsu.edu

What Disease?

If I had a wooden nickel for every time someone has said the following to me in the past few weeks, I'd be able to build a raging fire ... "I bet you are swamped with samples in the clinic right now with all the rain we've had, etc. etc., etc." Actually, outside of a few oddball cases, we haven't seen or heard of any major disease problems on creeping bentgrass putting greens. The missing link has been heat stress. If we look back at our records, some of our busiest years have been those that were hotter and drier which ultimately leads to more stress on the plant therefore making them weaker and more susceptible to infection by pathogens.

One of the oddball cases we have diagnosed in the past couple weeks has been summer patch on creeping bentgrass putting greens. The symptoms of summer patch appear as circular patches or rings, ranging from 6 inches to 3 feet in diameter. Turf within these patches initially turns off-colored, is prone to wilt, grows poorly, and may appear sunken in the turf stand. Over a period of a few weeks, the turf continues to decline, turns yellow or straw brown and eventually collapses to the soil surface. The outer edges of the patch are usually orange or bronze when the disease is actively developing. The patches recur in the same spot annually, and can expand at a rate of 2 to 4 inches per year.

Summer patch symptoms on creeping bentgrass

The summer patch fungus attacks the roots, stolons, and rhizomes in the spring when soil temperatures reach 65°F. Summer patch symptoms are rarely seen during the early stages of disease development, instead, the symptoms appear in mid-summer after considerable damage has been done to the root system. Heat, drought stress, and nutrient deficiencies are the main factors that encourage the expression of summer patch symptoms. In North Carolina, the symptoms typically appear in early to mid-July.

For more information about summer patch, including control recommendations, click here.

Finally, if any of you are wondering about Pythium root rot, we have only diagnosed a handful of cases thus far with all of those happening within the past 7-10 days. In every case, we have found the Pythium to be active in the upper thatch layer around roots closest to the plant. With that being said, if you are treating for Pythium root rot, don't water those fungicides in TOO much. We typically recommend about an 1/8" ... which in most cases equals about 3-4 minutes with part circle heads. Either way, you may want to take the time to see just how long it takes to put that amount out.

Pythium root rot following drainage route

For more information about Pythium root rot, including control recommendations, click here.

Fairy Rings and Fairy Tales

Fungi love water and here lately in North Carolina we've had plenty of water via record rainfall to help ensure they don't go extinct any time soon. The majority of fungi in this world are beneficial, because without these fungi we wouldn't have some of the finer things in life such as beer or Agaricus bisporus that adorns salads and pizzas as a topping. However, there are plenty of them that cause problems for us in the form of plant diseases.

You name a disease of turfgrass and we have likely observed it in the field or as a sample submitted to the NC State Turf Diagnostics Lab over the past 3-4 months. One that we rarely receive as a sample due to it's ease of identification is from a fairy ring. Most people associate fairy rings with mushrooms. To quote NC State alum Dr. Lee Miller, "not all fairy rings produce mushrooms and not all mushrooms produce fairy rings." This is important to remember, because if you observe mushrooms in your lawn, putting green, or croquet court, it doesn't necessarily mean you have a fairy ring problem.

A fairy ring in Raleigh, NC.

Fairy rings have likely peaked the interest of mankind since day one. This fascination has led to some crazy theories over the years such as fairies danced there the night before or that it was created by the fiery tail of a flying dragon. Whatever you do, don't step into the ring, collect the dew from the grass blades, or attempt to destroy it because bad luck is guaranteed to follow!

"Plucked from the Fairy Circle" - A man saves his friend from the grip of a fairy ring.

From British Goblins: Welsh Folklore, Fairy Mythology,Legends and Traditions (1880)

Fairy rings tend to form in circles, arcs, crescents, or broken rings. During their radial journey outward, fairy ring fungi decompose organic matter, which in turn releases nitrogen and other nutrients back into the soil for plants to take up. This is why the ring will often be darker green than the surrounding turf. The good news is that fairy ring fungi don't actually infect the turfgrass plant like brown patch, dollar spot, etc. The bad news is that they leave behind a coating on the soil particles that renders the soil hydrophobic (repels water) and may ultimately kill the turf. This is important to know when it comes to controlling the symptoms caused by fairy rings. For example, if you are treating fairy rings curatively in a home lawn situation, your best bet may be as simple as punching holes through the dead rings with something as fancy as an aerification machine or as simple as a pitchfork. Either way, you are instantly helping water penetrate the affected zone. If you are only observing green rings, then you may be able to mask them with a light fertilizer application. In severe cases or in high profile areas, you will likely want to use wetting agents and/or fungicides in addition to the aforementioned tips. 

For more information about fairy rings, including control recommendations, click here.

Guess What Now?? Brown Patch Blasting Tall Fescue in NC!

June is in full swing and so is brown patch in tall fescue lawns and landscapes.  Brown patch, caused by the fungus Rhizoctonia solani, is the most common disease in tall fescue during late spring and throughout the summer months in North Carolina.  Brown patch infections can start as early as April in some years with full blown outbreaks occurring by late May and early June in most years.  As the name implies, symptoms are brown to tan areas of turf that are roughly circular patches that range from a few inches to several feet in diameter.

Brown Patch Lesion on Tall Fescue Leaf

The two most common mistakes managers of tall fescue make are fertilizing too late or too much in late spring and over watering.  Tall fescue should not be fertilized after the first of May, unless you are using ultra low rates (< 0.25 lb N/M) with iron for a color effect.  The recommended amount of nitrogen on tall fescue per year is 3-4 pounds per 1,000 square feet.  Most people will apply a pound or two in the fall and a pound or two in the spring.  When in doubt, submit a soil test to ensure you're feeding your lawn the right nutrients at the correct amounts.

Watering should be done only as needed to prevent drought stress.  When you do apply irrigation, do it deep and infrequent instead of watering every day.  It is a common mistake for homeowners to set their irrigation system on a schedule and forget about it.  Remember, fungi love water and if you over water, you're giving the advantage to the fungi, not the turfgrass.  The ideal time to water your lawn is in the early morning hours before sunrise.  Irrigating during late afternoon or early evening is the worst thing you can do because this extends the leaf wetness period, however brown patch will love you for it!

Symptoms of Brown Patch in Tall Fescue

Need help knowing when and how much to water your lawn?  Try out our online water management tool at the following link.

http://turf-ims.ncsu.edu/

For more information about brown patch, including control recommendations, please visit the following link.

http://www.turffiles.ncsu.edu/Diseases/Brown_Patch.aspx

Guess What? Pythium LOVES Water!

If you've learned nothing else about turfgrass diseases, fungi love water and while not technically a fungus, the oomycete Pythium absolutely adores water. Now, you're sitting there thinking "boy, it sure has been wet lately across much of North Carolina, especially in western NC, and instead of reading this blog post, I should be firing up my sprayer and putting out something to prevent Pythium diseases." Well, if that's not the thought you had ... you better switch gears and make it happen.

Rainfall Estimates for Last 30 Days

For those of you managing bermudagrass putting greens or if you're trying to grow in a freshly seeded stand of anything, you better be on the look out for Pythium blight. We have diagnosed Pythium blight on 'Champion', 'Mini Verde', and 'Tifeagle' bermudagrass putting greens over the past couple of weeks. They are not bullet proof folks! We've also seen a lot of yellow patch on the ultradwarfs, but we'll save that for another day.

For those of you managing creeping bentgrass putting greens, you better be starting up your Pythium root rot prevention program. Two of the biggest misconceptions associated with Pythium and creeping bentgrass is that Pythium blight is common on putting green heights and Pythium root rot only occurs during the hot days of summer. Both are false. We rarely see Pythium blight on creeping bentgrass at putting green heights, especially if it's a well established mature stand. We have diagnosed Pythium root rot on creeping bentgrass putting greens in North Carolina in every month except the winter time.

For more information about Pythium blight and root rot, including control recommendations, visit the links below.

Pythium Blight

Pythium Root Rot

Dollar $pot Alert!

Over the past week, we have noticed a significant increase in dollar spot activity on creeping bentgrass putting greens at the Lake Wheeler Turf Field Lab in Raleigh, NC.

Dollar Spot Symptoms on Creeping Bentgrass Putting Green

Active Dollar Spot Mycelium after One Night of Incubation

The dollar spot fungus begins to grow and infect susceptible grasses in the spring when night temperatures exceed 50°F, even though symptoms of the disease may not appear until later in the spring or early summer. In addition, the pathogen requires extended periods of leaf wetness, 10 to 12 continuous hours. Heavy dews that often form during cool nights in the late spring or early summer are most conducive to the disease. Extended periods of wet, overcast weather can also lead to severe dollar spot epidemics on susceptible grasses. Dollar spot remains active throughout the summer in many areas, but disease activity typically slows when high temperatures consistently exceed 90°F.

Turfgrasses that are deficient in nutrients, especially nitrogen, are more prone to dollar spot and also recover from the damage more slowly than well-fertilized turf. The disease is also encouraged by drought stress, low mowing, excessive thatch accumulation, frequent irrigation, and low air movement. Certain cultivars of creeping bentgrass, perennial ryegrass, and Kentucky bluegrass are very susceptible to dollar spot, while others are fairly tolerant.

For more information about dollar spot, including control recommendations, click here.

It's Back! Large Patch that is ...

You know it's officially spring in North Carolina when there are giant patches of brown grass in bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass. These giant patches of brown grass are better known as large patch, caused by the fungus Rhizoctonia solani, and if you've ever had an outbreak of this disease, you now know why the disease was coined large patch.

What you may not know however, is what your control options are this time of year. You shouldn't worry too much if you have this disease on bermudagrass. Bermudagrass tends to grow out of the damage once the temperatures are consistently warmer and the daylight longer.

Large Patch Symptoms on St. Augustinegrass

As for our other warm-season friends, damage tends to be most severe on centipedegrass and recovery may take all summer in extreme cases. Unfortunately, there isn't much you can do to make for a magical recovery. We rarely recommend fungicides for large patch in the spring of the year, however in worst case scenarios, a fungicide application might help prevent the disease from spreading further. Fungicide applications are best when they are applied preventatively in the fall. If you choose to spray a fungicide this spring, don't expect a miracle to happen overnight. Also, remember that recovery will be even slower and tougher if you've applied a root pruning herbicide as your pre-emerge for summer weeds.

In most cases, the best thing is to stay the course with management practices that will encourage each type of grass to do well. In severe cases, treating damaged areas like a new establishment with light and frequent fertilizer and water inputs may help encourage faster lateral spread. This doesn't mean you should apply more fertilizer, just smaller doses more often. Applying too much fertilizer will make the disease worse this fall!

Finally, be sure to map the affected areas now while they are clearly visible. You will save yourself some money this fall by spot treating these areas instead of having to make a whole property application, since the disease tends to reappear in the same areas.

For more information about large patch, click here.

For more information about warm-season grass maintenance, click here.

Western Turf Conference March 12, 2013

The annual NC Western Turf Conference is nearly a week away on Tuesday March 12, 2013.  The conference will be held at the Virginia C. Boone Mountain Heritage Building at the Western North Carolina Agricultural Center in Fletcher, NC.  There will be a wide variety of presentations on golf course, home lawn, and athletic field management.  Registration and event information can be found here

Western Turf Conference Info

In addition to presentations on insect and weed management, the turf pathology group will be discussing anthracnose and bacterial disease on putting greens, maximizing fungicide performance, and managing diseases in home lawns and athletic fields.

Winter Patch Diseases Now Flocking!

Recent weather patterns, as weird as they may be, have been favorable for two common winter time diseases to start showing up across portions of North Carolina. They are Microdochium patch (a.k.a. pink snow mold) and yellow patch (cool weather brown patch).

As most of you know, Microdochium patch doesn't require snow cover and isn't necessarily pink in color, although if you look at the picture below, you can see that the mycelium does indeed have a pinkish tone. Infection areas may start out as small as 2" in diameter and expand up to 12" over time. The leading edge of the patch may have a reddish brown or salmon color and the leaves in the middle will be collapsed and matted upon themselves. Also, this fungus is a heavy spore producer, so the damage may appear as if it has been spread or smeared by mowers, equipment, water, etc.

For more information about Microdochium patch, including control recommendations, click here.

Pinkish Flock of Microdochium Mycelium

Microdochium Patch

Microdochium Patch

Yellow patch is a very common disease of cool season turfgrasses this time of year and typically causes irregular patches up to 3 feet in diameter that are yellow in color. On creeping bentgrass putting greens and other lower cut turfgrasses, it reminds me of sweat rings in an old ball cap.

For more information about yellow patch, including control recommendations, click here.

Yellow Patch on Creeping Bentgrass

Yellow Patch on Ryegrass