Having problems with my Marble Peppers

[Drakkar]

well My Marbles peppers were looking great, but i am having problems with the new pods are turning black and wrinkling up, and my mature pods that are turning from yellow to red, and are shriveling up. I know the sun is really bad right now in northeast Texas But i have a shade over them and they are getting plinty of water... what do i need to do,,, thanks