Is this plant cancer?

link to my flickr page, for some reason pictures do not post here.

A bit of history.
I planted this chayote plant from store bought chayote fruit. It grew nicely, and gave me lots of chayote squash and we ate lots of leaves as they are tasty and plentiful. I sprouted a few new plants from them, and new plants started growing properly, at first slow, then faster. However they stopped growing and became stunted, and this is what I noticed:

However they stopped growing and became stunted, and this is what I noticed:

Joy I don't know what's caused that and even been looking up, the only thing that attacks them is white flies and aphids.

Did you put any manure, hay, or straw on them?  Weird curling leaves can be a symptom of aminopyralid poisoning.