no index specific category

Is it possible in any way to make a specific category noindex ? I use an RSS feeder and I have alot of threads going on now.

is this going to work in robots txt ?

User-Agent: *
Disallow: /18-rss-category-name

Update

nop it doesnt work

I did this

Disallow: /index.php/Board/18-rss-category-name/

but the topics inside changes the board to threads

and are something like this

index.php/Thread/116-This-is-test/

so my robots command is useless here.