What do I need to cure this disease and what is it?

Thank you so much.

Looks like heat/drought stress to me. Are they getting enough water? If you can't increase water they might need some partial shade. Could also be from heat stress on the roots if they are potted and setting in the sun. Cure for that is to shade the pot or cover with al foil.

Under watering?  Does your pot get pretty dry between watering?

Mermaid - It always helps to tell us where you are located.  Tell us a little about the plant's environment, full sun, part sun, etc.  How often do you water it, when was it last fertilized, etc.

I think it is heat stressed.  here in NorthEast Texas we have had a record amount of rain followed by no rain and 98-99f heat so everyone's trees are stressed to some degree.

Move them to where they are in the shade for most of the day and see if it gets any better.
  Don't bother trying to save the current leaves, there isn't anything you can do for them.

Good luck

Cool that pot down during the day (shade). Set the pot in a large saucer made for big pot to catch water and hold a little water. I also use the black plastic oil drain pans from walmart but anything bigger than the bottom of your pot and at least a couple inches deep should do. It will probably hold water for a day, be dry for a day then next day water again. Every plant, size pot and soil mix has its own formula.

Probably needs water. That may mean more watering, more frequent watering, determining weather the soil is actually absorbing the water, or it is just running through the pot, etc.

Jon is right!  What it really means is the roots are not getting any water at all at the base or bottom!  The water is running straight through the pot.  The tree could also be root bound in a pot and the roots are touching the sides of the pot and when you water the plant's roots are cooled and wet for only a short time until the heat comes again.  If this continues, the leaves will dry up and new ones will appear---but what you have is a very good sign your tree is under stress.   

If the tree is inside a pot, get a huge sealed pot or bucket, add water and soak the entire tree in that for 30 to 40 mins.  I'd recommend up potting your tree to a larger pot but don't handle the roots too much.  Just get a huge container, add dirt, add water, add plant and add more dirt and more water and place in the shade for a few days. 

Thank you guys so much! It's been over 100 for the last couple days and I have only been watering it every other day.
Just transplanted about three months ago. So I will keep it wet. And mabe change the soil.
I live in maryland