Sharon is right - there is as many opinions on this as there are quilters :D Personally, I watch the fabric I use and test any darks I'm concerned about - but there are instances where I do pre-wash. When I do, I serge the cut edges of the fabric (a zig zag stitch would also work) to prevent fraying.
I've recently converted to Mary Ellen's Best Press instead of starch, and I love it! It is pricier, but no more gunk on my iron and it smells so much better! :D It seems to give me the same kind of control of the fabric without heavy feel of starch, and it doesn't contain any starch so no bug worries. :lol: