Question
I live in north central Texas, and it has been around 100 degrees the last couple of weeks. We had several pittosporum planted  this spring in various locations in our backyard. They were doing great, and just the last day, four in one area have developed light brown areas on the leaves that, when touched, crumble as if they are dead in those areas (the centers of the leaves). We have been watering via sprinkler system for 4 minutes twice a week as was recommended by our landscaper. Is this something caused by under watering, fungus, insects, or something else? Thank you for your time.

Answer
Pittosporum can take the heat, but it sounds like you are not watering enough.  I would water the plants by hose enough to make the ground moist down to about 4 inches, then do not water again until it dries up some.  The overhead sprinkler may be leaving water on the leaves which is magnified by the sunlight which may be causing the burn.  I would discontinue the overhead watering until cooler weather returns. Good Luck.