You Do Need power plug adapter while traveling from Argentina to Peru.

Here is Why You Need An Adapter

The outlet and plug type used in Peru are A, B and C and in Argentina are C and I. This is how they look like.

Argentina

In Argentina, outlets of type C and I are in use.

Type C

Type I

Peru

In Peru, outlets of type A, B and C are in use.

Type A

Type B

Type C