What defines organic food?

I was reading an article today about a new "green" pesticide that could be used on certified organic crops, and it set me to wondering. I used to use tobacco tea as a pesticide, but the recent onset of problems for honey bees made me reconsider the use of any wide spectrum pesticide. When I hear about "green" pesticides and "green" herbicides, I wonder about long term sustainability. I think we need another term, now. I think it would be more responsible to eat GM produce than that produced with wide spectrum pesticides, no matter how "green".