[slv77]

Monsanto engineered several crops to create their own insecticides with genes from bacillus thuringiensis (BT). BT corn was approved by regulators for corn not intended for human consumption.

In practice it became impossible to keep BT corn out of the food supply. With corn as a staple crop and the international trade in corn everyone on the planet became a test case.

There was controversy on the impact of corn pollen on non-target species, including monarchs and lady-birds/lady bugs and bees. Follow-up studies didn’t show significant impact in quantities likely to be encountered in the field.

All GMs have risk of pollen drift and the risk of gene spread. Farmers growing non-BT corn for export may have their crops rejected in some markets if contaminated. Corn cross pollinates with a genetic ancestor of corn in South America which is considered a weed because it can cause domestic corn kernels to not develop properly. There is some risk of gene transfer and creating a “super” weed.

https://ejbpc.springeropen.com/articles/10.1186/s41938-018-0...

https://ohioline.osu.edu/factsheet/agf-153