Wednesday, 14 September 2011

Shade and Its Relation to Turf Health

A few weeks ago I came across a really cool App for my iPhone.  It is called Sunseeker   and it allows you to see the path of the sun for any day of the year compared to what your phone "sees" through its camera.  This is a very powerful tool for superintendents.  Shade is a very big problem for most turf managers as it is very difficult to grow healthy turf if there isn't enough direct sunlight.  This tool can help you determine how much light your turf will get for any time of the year and also showcase which trees need to be removed to increase the available light on your grass.

#5 Green looking South East.  This green has high disease
pressure due to shade. 

This week the Fusarium returned to my putting greens.  During the warmer drier summer Fusarium usually isn't a problem as I usually have full control over the environmental conditions surrounding my putting greens.  This time of year I have almost no control over the conditions.  I cannot increase the air or soil temperatures nor can I stop the rain!  This makes it almost impossible to use cultural control methods to fight Fusarium this time of year (September).  So sadly my fungicide free summer had come to an end.

#6 Green looking South.  This green sees almost no
disease even in the winter months.
Now the Fusarium wasn't on all my greens and it also wasn't evenly spread across the greens that it infected.  It seemed to me that it was only infecting the parts of my greens that were in the shade.  It might also be important to note that I hadn't applied any fungicides in over 2 months on my course and I had at least 4 different fungal diseases on my greens.  These other diseases were Dollar Spot, Anthracnose, and Yellow spot.  Because my greens were chemical free for so long I could see the actual most susceptible areas on my greens.  I feel that if preventative fungicide applications are applied that the results could be skewed due to the control they provide.

  So I wondered how much shade were they getting versus the areas with no disease?  If I could reduce the shade during this time of the year on those highly susceptible areas I could potentially push my first fall fungicide app back a few weeks, or even a month.  So I set out with my new-found App in search of disease.

#4 Green looking South.  This green sees no direct sunlight
in the fall and has a very high disease pressure.
I decided to use the path that the sun travels during the Equinox.  This seemed like a good time of year to maximize the sunlight on my putting surfaces because  his time also matched the growing season on the West Coast of Canada quite nicely.  As each course is different it would make sense to adjust this date to suit the growing season that you observe.

  I divided each green into quadrants and measured how much direct sunlight potential each area had during the Equinox.  I recorded this along with the disease pressure that I had observed during that time period.  I was really only concerned with the Fusarium that was present and not the other "summer" diseases that I noticed.  I complied the data into a spreadsheet and organized the data according to the severity of disease.  This gave me a clear idea of how much sunlight I needed to reduce the severity of Fusarium this time of year!

Areas on my greens that received less than 3.5 hours of sunlight during the Equinox had the highest disease pressure from Fusarium.  Areas with 3.5-5.5 hours of sunlight had medium disease pressures and areas with over 6 hours of sunlight a day had no disease.

Fusarium on the back of #4 green.
With this information I now have a benchmark number of hours of sunlight that I can work towards.  Using the Sunseeker app I will now be able to remove trees around my greens that will maximize sunlight.  I also know that I only need 6 hours of sunlight to make a difference and don't need to remove trees if I already get 6 hours of light.  I will be able to use this tool to remove only trees that are absolutely necessary and I now have the data to back up the decision.

I highly recommend this app and I'm sure that it will more than pay for itself ($5.99) this next season.  In total it took me longer to type this blog out than it did to collect the data so you should have no excuse not to do this for every putting green on your course!


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