Icosahedron
SOC-14 1K
Emboldened and encouraged by the fact that we managed to keep the topic of atheism out of the pit, I thought I'd try another risque topic. 
If an invader (human, bug-eyed monster, or whatever) wants to take over a country or world in order to exploit its resources, and considers the indigenous (human) population to be an 'inconvenience', how easy/difficult would it be to completely eradicate the locals at different TL? What strategy/tactics would be most effective?

If an invader (human, bug-eyed monster, or whatever) wants to take over a country or world in order to exploit its resources, and considers the indigenous (human) population to be an 'inconvenience', how easy/difficult would it be to completely eradicate the locals at different TL? What strategy/tactics would be most effective?