What it is:
The genetic fallacy is related to appeal to authority in that information is judged as good or bad, or true or false, based purely on the source.
This avoids addressing the individual argument by shifting the focus onto where it came from. It’s also similar to ad hominem in that it leverages existing negative perceptions to degrade an argument without actually looking at the argument itself.
How to address it:
Ask the person to just look at the claim by itself independent of where it came from. Easier said than done, I know.
"You can't trust anything you hear from Big Ag."