Is deliberate genetic extinction of plant and animal species against intl law?
If the species is named in Endangered Species legislation, either international or regional, then it would be considered illegal, and any hunting, killing, or trafficing in the parts of the critter would be punishable by fines or prison terms – not just genocide, but any harm to the species. However, I’m not aware of any legislation that metes out specific punishment for extincting a species, although there probably should be.