"you can't compare DNA changes in a food stuff to a chemical acting directly upon the body, they are not alike."
Thats not entirely true, DNA encodes for different proteins, so if you change the DNA of a plant you change the proteins in that plant.
One example of DNA changes making plants toxic is Bt cotton, where the cotton plant has been modified to express proteins from the bacteria Bacillus thuringiensis.
These proteins are toxic to insects and protect the cotton from being eaten.
Perhaps varietys of Bt cotton or Bt maize are expressing these proteins in their pollen which i believe bees eat as food, perhaps that is whats killing the bees?
I think starlink, a variety of Bt maize, is banned for use in human foodstuffs because the type of Bt proteins it uses arent digested as quickly as other types of Bt proteins and there was felt to be a risk of a small number of people developing an allergy to it if it was allowed into human food.
And whilst this sort of GM crop may reduce the use of pesticides there is also the herbicide resistant type of crop that allow you to dump Glyphosate (Roundup) on to your crops to kill off the weeds, the crop will survive, I doubt this does much to reduce the amount of toxic chemicals used.
Dont get me wrong, I think there could be great benefits to humanity from GM crops, like the golden rice i think you mentioned in an earlier post, which could help in poor areas where vitamin A deficiency is a problem, but poor people dont have the money to pay for such things so arent going to be a target maket for the likes of monsanto.
Personally id like to see the genes from fireflys put into trees and moderated by the trees night time respriation so the trees glow at night, you could use them instead of street lamps, it would be awesome, you'd save loads of electric too.