Saturday, 7 July 2012

Double rolling and Fusarium, One Month later

Last month I came across the discovery that rolling might have an impact on Microdochium nivale or Fusarium Patch. Immediately after making this observation I began to roll my greens 2x daily as I had a serious Fusarium outbreak on my hands. It was the end of May and it had been over a month since my last fungicide application. Here is a picture showing just how much disease I was looking at.
Very Active Mycelium

I decided to give rolling a whirl. I waited an entire week after this picture was taken to apply a fungicide. I really wanted to give rolling a chance. I knew that rolling for curative control wasn't likely to work but what the hell? Rolling didn't seem to be helping after a week so I sprayed. When I sprayed I put down the sheet of plywood to really see if the fungicide application was actually needed. I was somewhat sure that I could grow out the disease but it was so widespread that if it really decided to take off I would lose a very large percentage of my putting greens going into the busy season. I just couldn't gamble on the unknowns. Furthermore the weather was bleak. Highs of 14-16C and rain....lots and lots of rain.
All of my greens looked like this. It was at the point where ball roll was not yet impacted but the potential was there.
I applied Daconil as it really knocks down the fusarium and is one of the best curative products I know of. It has a high Environmental Impact Quotient (EIQ) but I needed something that worked. This was the most widespread disease I had seen in 6 years. I had seen lots of disease damage over the years but I didn't want to let it get to that point.
Double rolling. Out and back on same pass. Different direction each day.
So a month later I can confidently say that that last fungicide application wasn't needed. The control plots were no different than the treated plots after a few days. The turf easily outgrew the disease and now there was absolutely no damage. At first I joked on twitter that I was going out with a "curative double roll" but looking back I think that the double roll definitely had an impact on the Fusarium.

Control Plots give meaning to inputs applied to the course. Without a comparison they are meaningless.
It's easy to say that you can not spray and let the turf outgrow the disease but really how do we know for certain that it can do this consistently? Since I have been collecting growth rate data since last fall I can see at what rate the turf was growing during that period and in the future compare it with those numbers. If I have growth rates similar to the ones I saw this spring then I can hold off spraying with a little more confidence that I had in the past. Each season I should get better and better at knowing when I can hold off with my fungicide applications. It is this kind of practical data collection that really makes decision making easier.

I also kept up with the 2x daily rolling until last week when we had so much rain fall that the greens started to get muddy. After a week long break of only rolling 1x per day and a raised HOC of 2.8mm we will be back up to 2x daily again next week. I am seeing again that rolling definitely has an impact on Fusarium patch. Last week during the wet weather the control plots on my trial green were caked in Fusarium patch where the plots rolled 2x daily again had no disease incidence. I was also seeing a great deal of Fusarium on my green collars as they aren't consistently rolled each day like the actual putting surfaces are. There was absolutely no Fusarium on any of my greens 1 month post fungicide application (not including Civitas or Phosphites) in weather perfect for fusarium to thrive! Now that the hot sunny weather is here any Fusarium that was around is all but gone.

"Control Plots give meaning to inputs applied to the course. Without a comparison they are meaningless."

Going forward I plan to continue to roll 2x daily to help with dollar spot control. I am pretty confident that I can keep dollar spot at bay with this combined with the phosphites and Civitas. I might be so cocky as to even stop Civitas and phosphite applications but I'm not sure yet...maybe a control plot or two... Last season I required one fungicide application for dollar spot in mid July. Next week should be interesting.

So with growth rates alone I should be able to combat Fusarium patch on my putting greens from May-Oct each season. Pesticide reduction? I think so! Add to this double daily rolling as conditions permit and I might just have this disease figured out. We will see. I am really looking forward to this fall to see how this all works when the turf growth rates start to slow down. How much rolling will be enough. Will it work in colder temperatures? How often can I roll when the turf stops growing? Can a model be developed to better understand and manage Fusarium patch? Am I just stark raving mad? All questions that I aim on answering this fall. I will keep you all updated on my less than scientific but practical observations.