Originally Posted by stevenf
There are no signs of pest or disease. What is the industry standard for irrigation timing? 3 days a week at 10 minutes does not seem like much to me.
There is no "industry standard" for irrigation. There are too many variables. Whether 10 minutes X 3 days is adequate or not depends on how much water the sprinklers are producing; what the plants requirements are; soil type; whether or not the water is adequate to perculate down to the root zone; drainage; rainfall; there is no quick answer.
There are a number of good suggestions here, going to the extension is one. From what you have said, everything points to an apparent over-watering condition, but I can't really tell sitting in front of my computer, and neither can anybody else.