What is going on with my raspberry plant?

I have three separate raspberry plants that I have taken good care of this year. Since the hot summer hit us, the leaves have died back. Now they are starting to gow back from the buds. The two outside plants are looking great, but the middle one is wilting, as if it is about to die. I have watered them all the same and they all get the same amount of sunlight. Now, there was a sucker in the ground, trying to grow another plant, that i pinched off at ground level. What can I do to possibly help the plant?