Question
QUESTION: I keep my st. aug (raleigh) cut at the highest level my mower will cut.  I have been fighting gray leaf spot for several weeks.  Firstly, is there a problem with the height of my grass in dealing with diseases.  Secondly, is there a good way of getting rid of and preventing gray leaf spot.  Lastly and somewhat off topic, my newly sodded back yard is not near as thick as my from.  I understand that it is new and will take time.  My question is how much time before my back yard is thick like the front??

Thanks for your time

ANSWER: Hi Dusty, I'm not that concerned about the height, although taller grass dries slower than short grass.  Bag your clippings to prevent spreading the disease.  Use either Bayleton or Propiconazole to cure the problem.  It may take a couple of applications and summer heat helps slow the spread.  Always irrigate in the morning so the grass dries quickly.  
Make sure your subsoil pH is 6.5.  Mow it lower and more frequently to encourage it to grow sideways instead of up. Fertilize very lightly twice a month.  I'd use fertilizer at 1/4 the label rate.
If your subsoil was properly prepared when the sod was laid, you should have a decent stand by year end.  Jim

---------- FOLLOW-UP ----------

QUESTION: Thanks Jim

YOu say to mow it lower...wont that encourage weeds and/or burn the grass with the heat in Louisiana?

Answer
Worry about weeds later.  You can always get them out. You want to encourage tillering, the side production of shoots.  That's done by mowing lower and more often. You should be watering infrequently but thoroughly to encourage deep root growth, so you should not see any stress unless you are improperly watering.  I am curious about why new sod isn't thick and lush. Usually it looks great when it's laid.
Instant lawn.  If it's gone backward, then I'm concerned about the subsoil prep and your watering.  If it wasn't thick and green when laid, then I'm concerned about the quality of the sod. If it was sprigged, then you should be mowing low and frequent.  You should never remove more than 1/3 of the leaf blade when you mow, so base your frequency on that.  Jim