Who does Candy blame for the destruction of his dream? Curley's wife or Lennie?

I think Curley's wife. Candy initially warns George and Lennie about Curley's wife. All the men were afraid of her advances lest they lose their job. Lennie didn't know any better.

Here is a good quote from chapter 5.

Old Candy watched him go. He looked helplessly back at Curley's wife, and gradually his sorrow and his anger grew into words. "You God damn tramp", he said viciously. "You done it, di'n't you? I s'pose you're glad. Ever'body knowed you'd mess things up. You wasn't no good. You ain't no good now, you lousy tart." He sniveled, and his voice shook. "I could of hoed in the garden and washed dishes for them guys."