Why TWO "junk mail" folders?

Hi all. Last week, I turned on spam assassin in the Dream Host control panel, set the threshold and tags to recommended settings, tweaked it for the next few days. That did seem to help reduce the spam getting through.

BUT… there are still messages going to a different Junk (“domain name” IMAP) folder rather than the “Junk Mail” folder. Here’s the hierarchy now as seen in Squirrel Mail:

    Apple Mail To Do
    Deleted Messages
    Junk ([domain name] IMAP)
    Sent Messages

Junk Mail (0)

I don’t know what the distinction is, but the IMAP junk folder items still gets forwarded even though they’re clearly spam. Items that go into the “Junk Mail” folder don’t get through, which is the preferred behavior.

The IMAP junk folder does not have the “blacklist/delete” option or any other apparent way to move the items to the primary, more-robust “Junk Mail” folder. If anyone can help clarify this situation, I’d appreciate it.

I have a similar setup, though I have a Spam and a Junk Mail that shows up. Junk Mail is more like the local quarantine controlled by SpamAssassin, and Spam is what Mail.app uses. Clearly, Junk Mail doesn’t fall within the INBOX hierarchy, so it’s not shared by IMAP.