Program '11 Update: Dollar spot and Pythium root rot

We're only two months into our Program '11 Project and are already seeing major differences among the fungicide programs we're evaluating. Here's an update on things:

We've already made a number of changes to the Program '11 treatment because of the continuing cool and wet conditions. Dollar spot pressure has been very high for the last month, and frequent rainfalls have increased the risk for Pythium root rot development. Here are the changes we've made so far:

1. We were scheduled for a Bayleton application on April 4 for fairy ring prevention, but the soil temperatures were too cool. Instead, we moved-up the application of Honor originally scheduled for April 11 because the weather was very favorable for Pythium root dysfunction and dollar spot.
2. The Bayleton treatment for fairy ring was applied on April 18 when 5-day average soil temperatures finally reached 55F.
3. Due to an outbreak of dollar spot in the Program '11 plots, we made an emergency application of Daconil + Torque on April 29. Therefore, we cancelled the application of Torque that was originally scheduled for May 2.
4. Instead of applying Signature + Banol on May 9, we decided to go with Banol + 26GT on May 12 due to continuing dollar spot pressure and wet conditions favorable for Pythium root rot.

Now to the results:

• Clemson's Program 13, which hasn't received any fungicide treatments yet, is getting hammered by dollar spot as you would expect
• The NC State Program has also failed to provide acceptable control of dollar spot. This is probably due to the intense dollar spot pressure this spring combined with the watering-in of most treatments for fairy ring and PRD.
• The Bayer, Syngenta, BASF, and Program '11 treatments are providing good to excellent dollar spot control.

Turf quality is primarily being affected by dollar spot, so the treatments that are providing good dollar spot control are exhibiting the best turf quality right now. The Bayer and Program '11 treatments have the highest turf quality because they are providing the best dollar spot control. Program 13 and the NC State Program are not providing acceptable turf quality at this point.

For more information about our Program '11 Project, or to follow along on Facebook or Twitter, please visit our website turfpathology.org.

Program '11 Project: Here are the programs

As part of the Program '11 Project, we will be evaluating several popular fungicide programs for creeping bentgrass greens, and comparing them to a program that we developed for our specific location (NC State Program) and another program that is modified based on this year's weather conditions (Program '11).

You can find all of the details of each program by following the links below:

1. Program 13 from Clemson

2. BASF Program

3. Bayer Program

4. Syngenta Program

5. NC State Program

6. Program '11

We'll be providing regular updates during the season on the performance of these programs and how we've adjusted Program '11 based on this year's weather conditions.

For more information about our Program '11 Project, or to follow along on Facebook or Twitter, please visit our website turfpathology.org.

Program '11: An example fungicide program

Following the steps I outlined in my last post, we developed a fungicide program for an 'A-1' creeping bentgrass putting green built to USGA specifications in 2005. 

Located on our Lake Wheeler Turf Field Lab, this green has a history of Pythium root dysfunction and fairy ring problems, and we were also hit with Pythium root rot last year during an extended period of wet weather. Dollar spot, brown patch, and algae are also problems on this green as they are on most bentgrass greens.

We used an excel spreadsheet to assist with developing the program. The diseases we need to control were listed at the top, with each column across the sheet corresponding to a week during the growing season. Using our knowledge of the weather conditions that trigger each disease and historical weather data from the State Climate Office of North Carolina, we highlighted the weeks that each disease is likely to be active. This gives you a good visual image of what diseases need to be controlled with each fungicide application. We used the Disease Management Utility on Turffiles to select a fungicide or tank-mixture that would control the diseases that are expected to be active during each week. We tried to avoid having to make fungicide applications on back-to-back weeks, but in several cases we needed to do that because application methods (foliar vs. watered-in) were not compatible.

Here's the program we came up with:

March 14:  Segway (0.9 fl oz, watered-in)

April 4:  Bayleton (1 fl oz, watered-in)

April 11:  Honor (1.1 oz, watered-in)

May 2:  Torque (0.6 fl oz, watered-in)

May 9:  Signature + Banol (4 oz + 2 fl oz)

May 23:  26GT + Fore (4 fl oz + 6 oz)

May 30:  Terrazole (4 oz, watered-in)

June 6:  Disarm C (5 fl oz)

June 13:  Subdue Maxx (1 fl oz, watered-in)

June 20:  Honor + Fore (1.1 oz + 6 oz)

July 5:  Signature + Daconil Ultrex (4 oz + 3.2 oz)

July 11:  Segway (0.9 fl oz, watered-in)

July 18:  Disarm C (5 fl oz)

Aug 1:  Stellar + Daconil Ultrex (1.2 fl oz + 3.2 oz)

Aug 15: Spectro + Alude (5.76 oz + 6 fl oz)

Aug 29:  Subdue Maxx + Fore (1 fl oz + 6 oz)

Sept 12:  Reserve (3.2 fl oz)

Sept 26:  26GT + Daconil Ultrex (4 fl oz + 3.2 oz)

If this seems like a lot of applications and an expensive program, you're absolutely right. Several of these applications are specifically to control Pythium root rot, which can develop any time between May and October in North Carolina depending on when the wet weather comes. This is why adjusting your fungicide program based on the current conditions is so important - many of these Pythium applications could be avoided if the weather is dry and unfavorable for Pythium root rot development at that time.

This year we'll be comparing this NC State program to other common fungicide programs, and one that we adjust on the fly based on the current weather conditions, to see which method provides the best disease control and highest turf quality. 

For more information about our Program '11 Project, or to follow along on Facebook or Twitter, please visit our website turfpathology.org.