Coming in Jan 2013: Dr. Jim Kerns!

Recently the department of plant pathology at NC State University graciously offered me the turfgrass pathology position.  Turfgrass Pathology has a long, storied history dating back to Dr. L.T. Lucas.  Many may know that I have a small part in the history of turfgrass pathology at NC State.  I had the great pleasure to have Dr. Lane Tredway as my major advisor during my PhD while I was at NC State.  There is no doubt that Lane built a Ferrari of a program and I am very much looking forward to driving this Ferrari.  Undoubtedly I will drive this program in a different direction, but I assure you I will do everything I can to provide value and service to the turfgrass industry of North Carolina.     

For the last 4.5 years I have built a program in turfgrass pathology at the University of Wisconsin-Madison.  While there my program focused on diseases of cool-season turfgrass and in particular, dollar spot and snow molds.  I built many great relationships in Wisconsin and I will miss working with the great industry there.  This is a huge change moving from Wisconsin back to North Carolina and I will likely require an education from you all on what is important to you.  I am very much looking forward to working with all of you and seeing what we can accomplish together.  My official start date will likely be in early Janaury 2013.  Prior to this, I am happy to discuss research ideas or areas of need and I have listed my current contact information below. 

Jim Kerns

(608) 516-8917

jkerns0@gmail.com

Treat for Large Patch Now!

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

Average Daily Soil Temperatures as of 9/18/12 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 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.

Click here for more information about Large Patch, including images and specific control recommendations.

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.

Average Daily Soil Temperatures on 9/15/12 via NC State Climate Office

As you can see by the map above, the time is right for preventative applications. However, 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.

Also, if you haven't heard, Rubigan will be coming off the market in December of 2012.  Rubigan is one of the better fungicides available for spring dead spot control.  To learn more about this, click here.

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

15 Minutes of Fame for Leaf Spot

After looking back through prior alerts and posts, I discovered that leaf spot diseases have never made the cut, until now.  Recent weather patterns of cloudy and rainy weather across much of North Carolina have been perfect for foliar diseases such as Bipolaris leaf spot and gray leaf spot.

Bipolaris Leaf Spot on Bermudagrass

We have received several samples of bermudagrass in the past week 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, drought stress, and low mowing heights are factors that encourage the development of leaf spot diseases.  These fungi may spread to the crowns and roots and cause melting out, which is most severe during periods of hot weather.  For more information about leaf spot, including control recommendations, click here.

Gray Leaf Spot on St. Augustinegrass

We have also received several samples of gray leaf spot on St. Augustinegrass here at the NC State TDL. Proper mowing practices are most important for gray leaf spot management in St. Augustinegrass. This grass must be mowed frequently during the summer months to remove excess leaf tissue, keep the canopy open and dry, and remove developing gray leaf spot lesions. Collecting clippings reduces spread of the disease when gray leaf spot symptoms are evident. Apply nitrogen and other nutrients as recommended to maintain vigorous foliar growth during the summer months. Excessive shade, in addition to promoting leaf wetness, slows St. Augustinegrass growth and enhances gray leaf spot problems. For more information about leaf spot, including control recommendations, click here.

The Rundown

After a relatively quiet June at the NC State Turf Diagnostics Lab, turf samples have been rolling in during the month of July. Right after the record breaking heat wave experienced by North Carolina and much of the country, it seemed as if delivery trucks were backing up and dumping cardboard boxes of all shapes and sizes chocked full of ailing turfgrass samples.

One of the most common questions I get from golf course superintendents that I speak with on a weekly basis is "What are you seeing in the lab?" Well, here you go! Here's a rundown of the most common diagnoses we've made over the past two weeks.


Creeping Bentgrass Putting Greens

1. Pythium root rot
2. Fairy ring
3. "Warm-weather" brown patch (Rhizoctonia zeae)
4. Yellow spot
5. Anthracnose

Home Lawns

Zoysiagrass

1. Curvularia leaf spot

Bermudagrass

1. Heat/drought stress

Tall Fescue

1. Brown patch

Summer Solstice Welcomes Brown Patch

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

Pythium Root Rot: History Repeating?

The summer of 2010 shouldn't be too distant of a memory for most and if you remember correctly, most of NC ended May on a very wet note. This was followed by one of the hottest summers on record. This series of events led to widespread cases of Pythium root rot on creeping bentgrass putting greens, especially for those who did little to nothing to protect their roots from Pythium during May.

With all that being said, you should be applying products for Pythium root rot prevention RIGHT NOW.  Doing so now will save you money and headaches come summer.

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

Remember that Pythium root rot is a soil disease, so you MUST water your applications in to be effective.

May 2012 Rainfall Total

May 2011 Rainfall Total

May 2010 Rainfall Total

Severe Large Patch Outbreaks in NC

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.

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 DNA type of 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.

Status Update: The Show Will Go On

Beginning February 1, I've accepted a new position with Syngenta as a Senior Technical Field Representative for Turf and Landscape. I'll be covering the Southeastern US and will stay in the Raleigh area.

The Turf Pathology Program at NC State has a long, proud history, dating back to the 1970s with Leon Lucas. I wanted to assure everyone that this program will continue to operate as normal (perhaps even better without my interference) during the transition period until the faculty position can be refilled:

• Lee Butler will continue to oversee the Turf Diagnostics Lab as he has since 2005. For information on how to submit a sample, visit the website www.turfpathology.org. 
• Mike Soika will continue to run the Fungicide Evaluation Program to gather valuable data on the performance of new and experimental fungicides.
• Bangya Ma, Alex Putman, and Joseph Roberts will continue their research on dollar spot, bentgrass etiolation, and other important problems in the turfgrass industry today.

I want to sincerely thank everyone in the turfgrass industry for your support since my arrival in 2002. It has been a pleasure to work with all of you, and I am proud to look back on what we've been able to accomplish together. I am looking forward to the new challenges that lie ahead and to maintaining a close relationship with this great industry in my new role with Syngenta.