This afternoon I found something I've never seen before, black spots/blotches on old needles of one of my JWP. I can't imagin it being root rot, since it's in inorganic substrate and I only water when necessary. I also read that JWP are substantially more resistant to needle cast/other foliage attacking fungi, so I have no idea what this is. I naturally removed all the infected needles, but I hope this doesn't come back and spread! Pines cannot afford to be defoliated like deciduous!!

Any ideas on what this is??

T