How to tell Google that directory doesn't exist anymore?

I created health-related site based on Joomla. I created Google Webmasters account and saw how Google indexed my site. But then I saw that Google indexed some directory /includes (that I didn't create) and which content was far from health topics. I deleted this directory, but already for 2 months Google Webmaster shows top keywords from /includes directory.

What should I do to tell Google that directory doesn't exist开发者_运维百科 anymore?

Thank you in advance. In case you need, here is address of site: http://healthfount.com

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You need to create a robots.txt file for your site.

see here