dissolve or emit start point

How do I get the particles to remove starting at the top of the spear

and finishing at the bottom?
also question number 2. How can I reverse animation render / start at 250 and end at 1.

Ill put this in different words.
I made a animation ( not above example ). I made 5 copies of a object . I deleted some of each and kept parts of each top, middle. bottom… 5 objects to look like one and set the start times in particles to delay on 2,3,4and5 object. so it looked like it dissolves from top top bottom. Is there a more easy way for this?Its so much work.
I can not view a tutorial over 15 mb so I have not seen how others do it.