There is a basic misunderstanding being presented as the truth re glyphosates use before roundup ready crops came to market . The claim is that glyphosate was used on crops for 20 years before roundup ready crops came to market . There is a sliver of truth to the claim but it is far from the truth . It is misleading , it presents a false picture of the past and present use and abuse of glyphosates .
Glyphosate kills crops that are not genetically modified organisms with a tolerance for direct glyphosate application . Glyphosate accidentally applied to a non "GMO" / roundup ready crop would kill the crop . Glyphosate drift into a crop nearby would cause the death of the crop that the glyphosate accidentally got onto . Glyphosate applied to the soil would have to be applied far enough ahead of planting so as not to kill the crop as it was planted .
If before the non roundup ready crop was fully grown some glyphosate was applied to the crop the crop would be ruined . Farmers who accidentally applied glyphosate at the wrong time would kill off their crop accidentally .
There are times when glyphosate is intentionally applied to non GMO / roundup ready crops . It is used to intentionally kill the crop . If a farmer decides that the crop is not going to work for them , if the market for the crop goes to heck , they can kill a whole field and hopefully all the weeds at the same time so as to get the field available for another planting .
Another use of glyphosate on a non GMO / roundup ready crop is at the end of the growing just before harvesting . Dead crops are less work for machine harvesting . So the farmer sprays glyphosate to kill off the plants to get them all dead and ready for harvesting . If there are patches in the fields of green healthy plants and or patches of green healthy weed , those green healthy plants / weeds take more effort to harvest from and around . The farmer can and will spray those green plants with glyphosate to get a uniformly dead field to run their harvesting equipment on .
If a field is planted with a GMO / roundup ready crop and the crop is ready for harvest but there are "roundup ready / superweeds" greens , then the farmer can go out and give the "roundup ready / superweeds" a massive dose of glyphosate to try and kill off the weeds without overdosing the crop and killing the crop before it is fully grown .
The killing off of a crop with glyphosate to ready it for harvest is called desiccating .
Removing the water from the plants , killing off the green healthy , weakens the plants so they can be cut / harvested / processed with less effort .
Crop desiccation with glyphosate is one of the ways glyphosate gets into a non GMO crop . There are non GMO crops that are turned away from some markets because they are found to contain higher levels of glyphosate than allowed by local regulations .
If a non GMO crop field is sprayed with glyphosate to desiccate the crop , the field is also treated in the sense that the weeds are hopefully killed off before the next crop is planted .