Thursday, 30 May 2013

"The Best Laid Plans...."

Well I broke down today and sprayed a traditional contact fungicide on most of my greens. I just wasn't confident that I could recover from the recent fusarium outbreak without it. Everything seemed to be going really good until yesterday when the turf growth rates exploded as did the fusarium activity. It would appear that the turf has finished its seed head production cycle and has now gone back to some serious vegetative growth again.
One of the less infected areas. Still green from a recent Civitas application.

Making the decision to spray was difficult because I really wanted to see if I could make it until the summer without the need for conventional pesticides. As usual I left some knock out areas to see if I could in fact outpace the disease without the contact pesticide. This time last year I did almost the exact same thing and the knock outs suggested that I did not need a fungicide. This is why the decision to spray this year was even harder this time around.

I had to weigh my options and make a decision that I would feel comfortable moving forward with. There were a few things that made me feel comfortable and these were:

  • The forecast was favourable with dry warm conditions.
  • Growth rates were relatively high to outpace the growth of the disease
There were also a few things that made me very nervous:
  • The overall cover of the disease was very widespread. If things turned sour there would be very little grass left after a few days. This is bad just in case you need clarification. This issue was made worse due to the natural Poa annua thinning following seed head production.
  • I hadn't applied really any products with significant fungistatic properties in almost 7 months. Aside from the small amount of sulphur there was little in my program that actually had any direct effect on the fungus. Civitas and Phosphite mode of action is primarily indirect. So there was basically nothing to stop the disease except for the plant's natural defences which leads me to my next point.
  • The Poa annua had just come out of seed head production which is pretty stressful. There is a natural turf decline following this phenomenon and most turf managers are especially careful during this weakened time of the year.
  • I didn't want to increase sulphur rates as this could stress the poa out more which would make things potentially worse.
This is why I decided to err on the side of caution and experience and spray.

The active disease has been active on the greens for months now but hadn't seemed to be spreading at all. This is one of the issues I see with only using indirect fungicides in your disease management program. Sometimes you just need to hit the fungi directly with something that really works! There are currently limited organic options with direct fungistatic effects that really work. I tried zerotol with no success last year.

I like to look back at my disease management program to see where I could improve next year. I think that my seed head management program might cause some of the disease issues and maybe some adjustments are needed to balance playability with disease management. I also over-applied nitrogen the past 2 weeks because of stupid math errors. I can only wonder what might have been. Or maybe I am doomed to have to spray a traditional pesticide whenever the poa goes out of seed head production. I guess that is one of the issues with  Poa annua. I was starting to think that I would be able to do this with the Poa but this is just another case for bentgrass. If only I could get it to grow here....
Who Knows?

Other things I would try differently would be to apply the civitas and phosphites more frequently through this period of stress. Maybe that would help?

This is one of the reasons I have been hesitant to fully commit to my program. This stuff is unproven and blindly committing to an unproven method is insane. I wrote about this issue with organic golf last summer.

I have to take away the positives from this though. I made it through the winter without traditional pesticides, something I once thought impossible in my climate. Now I just need to figure out this late spring and summer thing.

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