IP-block = ban from search engines (?)

Hello,

Does anyone know if IP-blocks will make it harder to get indexed on a search engine, such as Google?
I want to block a whole country...

what software?

Are you referring to blockhosts? It does not block whole regions, just single hosts. Therefore blockhosts will not any impact in blocking any web crawlers - possible of course, but unlikely.

If you generally blocking large ranges of IP addresses using some other software, then, sure, you could also block legitimate web crawlers.