Submit button in Insert Statement

[eluser]Fielder[/eluser]
When I use $this->db->insert('bus',$_POST); in my method, it tries to insert my <input type="submit" name="submitnew" value="Submit" /> into the database. I get a returned error telling me the field submitnew is not in the table. ...but I dont want to insert it into the table. Am I missing something? I've never had to worry about this before.

Thanks.