Thanks for the reply. Plants are strong and vigorous - 5' and still growing. Other varieties are setting fruit and doing well. I've had problems with this variety in the past, but when they do set fruit it is plentiful and very flavorful.When you run into this problem try altering the watering rotation on that plant. Try increasing it. Also you can look at if the roots are too small compared to the top plant size or vice versa. (Is it damaged or getting heat stroke...?)
Another thing you can look at is if that type of variety or seed is well suited to your climate.
Is your area getting water or drought problems? (A lot of the areas in the midwest, grain belts, and the east coast and south are having tons of troubles right now.)
I hope this gives you some ideas of some things to try and things to be aware of. Feel free to post any follow up questions, etc.