Is biofuel helpful or harmful?
Right now, I think the crop issues are a red herring, meant to slow the conversion so that oil companies can scare us into allowing more drilling, leaving them in power.
All portions of the same crop plants can be used in biofuel manufacture, not just the edible portions, and insecticides probably don't survive the processing, so they aren't an issue, IMHO.
Biofuels can definitely be helpful if people stop buying into the fear factor and get busy making the transition.