We really need pictures to help you...the problem may not be needle cast at all.  It would also help knowing what type of soil the tree is in, how often it is watered, fertilized, etc.

Dave has a good point: pictures would help.

Hope this tree pulls thru for you! I know what it is to lose a yamadori ponderosa that is one's "pride and joy."

I didn't see it till I got home so I didn't talk to Andy about it.  I don't have a macro lens, so these are the best I could get.  But you can see the black bands on the needles if you look close.

John, you don't think those black bands are needle cast?? Seen quite well on image 1144.  It looks just like the pictures I've seen on the net.  And I showed the pictures to the curator of the bonsai collection at the Chicago Botanic Garden and he thought it was needle cast too.

That being said, I have been keeping the watering low/on the dry side, due to reading they don't tolerate wet roots well.  Plus, Andy has this planted in Turface and grit, so it drains real quick after watering.  On the other hand, I also read that overwatering can lead to brown tipped needles.  So, I'm a bit confused.  This is a hard topic to convey over the internet imo.  

Thanks John!  It's very nice to hear I'm not killing it )  I think I just need to get to know the watering requirements better on this PP.  I'll keep up on the Daconil, and, I'll keep it a bit wetter now; before I stuck my finger into the inorganic mix about 3" to check moisture levels.  I think I'll cut that down to 1-2".  I also moved it to a better location yesterday, getting more sun and air circulation.

 I also just this week changed my ferts from fish emulsion to 0-10-10 though I'm wondering if I'm doing this too soon?   The weather has been in the high 50s to low 60's and nightime has gone down to the 40s.  But this crazy weather here, we're supposed to get back up to the 70s for awhile.  (I lost a tropical cutting and my azalea last week when the weather went from 86 to 56 at night.  I'm not used to the weather here yet, so lesson learned)