You Do Need power plug adapter while traveling from Solomon Islands to Botswana.

Here is Why You Need An Adapter

The outlet and plug type used in Botswana are D and G and in Solomon Islands are G and I. This is how they look like.

Solomon Islands

In Solomon Islands, outlets of type G and I are in use.

Type G

Type I

Botswana

In Botswana, outlets of type D and G are in use.

Type D

Type G