Monday, 25 February 2013

Late February Disease update and Plan

Happy February! Still no synthetics here!
If you would have asked me last September if it was possible to grow Poa annua putting greens without the use of synthetic pesticides over the winter I would have called you crazy. It is now almost March and I have 3 greens that have gone without synthetic pesticides since September and one green since June! The toughest part of the fusarium season has past but it is far from over!

For the most part I feel that the overall disease pressure this fall and winter has been low. We had an extended dry period this fall and the winter wasn't that cold or wet. February has been very mild and the turf has really started to grow.

A little R. cerealis showing up again
Currently the only troublesome turf diseases thy are active are M. nivale and R. cerealis. Tees and fairways have a moderate amount of fusarium and the approaches have an extreme case! The greens have had almost no fusarium activity all winter but I did apply two fungicide treatments to a few greens that were damaged from frost and I wanted to protect the weakened stand from further damage. My synthetic pesticide free greens have a low amount of fusarium patches present (can count on two hands) but I am closely watching them. I have resorted to plugging out the patch to prevent the spread of disease from my mowers with great success. The active R. cerealis is slow going and I doubt it will become a problem as the growth rate of the turf will only increase. I will closesly monitor it's activity and will spot apply nitrogen if needed.

A rare occurrence this winter.
Last summer I made a plan to combat fusarium and for the most part it worked. With any plan there are always kinks and things that didn't quite work out as planned. This winter I wasn't able to roll as much as I would have liked as we had issues getting enough sand down in the fall and the greens became too soft to roll aggressively over the winter. I was only able to roll twice for every time I mowed the greens so unfortunately I do not believe that rolling had a part in my successes this winter. I also think my plan to reduce nitrogen rates was good but this carried it's consequences with the R. cerealis outbreak in November. This fall I didn't fully understand the power of nitrogen in winter disease management and paid the consequences. This has all been new territory for me and mistakes are bound to happen.

I wonder if this guy uses Civitas? hmmm
My plan going forward is to continue with my regular phosphite and civitas applications on greens. I am still slightly skeptical that these products are the reason for my success so I will also resume knock out areas on each green to check my suspicions.

What I really think is the reason for my disease control success has been judicious nitrogen applications. In the past I had always applied a slow release nitrogen source in the fall. This year I have stuck with strictly soluble sources based on growth potential calculations. My recent observations have only confirmed my nitrogen suspicions.

In the next month I am going to fight the urge to apply any nitrogen (soooo hard) as the turf slowly awakens from its winter slumber. In the past I always wanted to push the spring growth to get things moving. What I have learned this past year regarding growth rates is that it is more about the temperatures than how much nitrogen you apply. It is far safer to apply too little nitrogen than too much as you cannot take back any nitrogen that has been previously applied.

The Plan Works. Last synth pesticide app
was Daconil 2787 June 6 2012
While the way I have been fertilizing my greens for the past half-season has been very successful I feel it has a few limitations that I am going to try and work out. The growth potential is great for a starting point to determine nitrogen applications but doesn't take into account the different micro-climates on the course. I have never really had a decent weather station on the course except for a hand held unit that would give me current data with no logging function. This year I have purchased a few Specturm Tech A-Series Data loggers  which I will be able to place around my course to get a better idea of what differences in temperature exist on my course. No, I do not plan on having a sensor on each individual green (maybe next year) but I do plan to measure the average temperatures and adjust my nitrogen applications for each green accordingly if a significant temperature difference occurs. I have a few greens that only receive a half hour of late afternoon sun for over half of the year and I am certain that the temperatures difference on these greens will make an impact on my fertility requirements. This fall my shady greens tested at almost double the nitrogen in the soil which suggests that the plant is using less due to a slower metabolism.

I tried to save this tree but....
On an even smaller scale I have areas on some greens that always get the fusarium first. These areas are usually to the south and heavily shaded compared to the rest of the greens. Long term the best solution is to try and provide an even amount of light to all areas of each putting green which will require more tree removal. I don't think I need full sun but I do feel that it would help to have each green receive a consistent amount of light over its respective surface each day. In the short term I plan on maybe skipping nitrogen applications on the usual suspect locations unless I feel that the turf can outpace the growth of the pathogen (mid-April onward).

Can you see the light?
The next month is going to be a real test. With active disease on my synthetic pesticide free greens I cannot afford any mistakes. If you see me tweeting about an upcoming nitrogen app in the next month tell me to stop. I am going to try and hold off anything drastic but I can't promise I won't put out just a little bit (0.006kgN/100m2/week maybe?) It's not easy changing a bad habit OK!

I know what you're thinking. "With all these different nitrogen rates isn't that going to lead to inconsistent playing conditions?" It might, but wouldn't you think that the micro-climates would contribute more to any variances you would encounter? As always I will be monitoring this as well to ensure that things don't get silly.

And of course I could be completely delusional and all of my success could have been a fluke! I really hope this isn't the case but time will surely tell!


Spring is almost here again!