Thanks for the response Fruitnut. I will keep an eye on it. The thing is, I'm not too invested in the tree. The two varieties on it are interesting but nothing I'm dying for and they aren't so far along yet that starting over would be too demoralizing. It was cool that this tree was grafted by me on rootstock that I propagated myself. On the other hand, I have a number of other stone fruits near it, some of which are much better established. If this were a greater than 5% chance of being plum pox I'd want to dig it out and burn it ASAP to avoid spread in the orchard. It sounds like it is probably sub 5% so I will wait and watch. BTW, did the USDA tell you what caused the symptoms that you were concerned might be caused by plum pox virus?

It's called heat and drought :-) Some trees react more severely than others. Unless that color change is also accompanied by dry, crisp foliage (can't see at that distance), I'm not sure you have a lot to wrry about. If the drought persists, a few deep waterings should help.

The first thing to do would be to pull back the carpet. That will tell you if the floor is wet. I would probably them pull of that baseboard strip -- if the wood is still sound, you may clean it up and replace it or just replace with new. There should be a gap between the drywall and the floor. I would look for moisture there. before tearing into the wall, I would follow anything you see up and look for possible damage above -- water stains, loose tape joints, any swelling or buckling. Look up and see what possible sources are above as well as outside (sprinkler head, pooling water, etc.). If you can determine the area of the source, you may not need to do as much damage to the wall that will all have to be repaired. Is there a bathroom above? a water line that runs across? Hot water heater or AC drain overflow that could have backed up? See what you can about those potential sources from above and outside and see if you can save yourself some work and money. We discovered a problem the previous owners covered up with paint when we removed a baseboard to put down new flooring. It came from the upstairs bathroom, but only the baseboard needed to be replaced and everything else cleaned up fine. .

It definitely doesn't look like poison ivy or oak to me, but I must admit that I can't quite be certain because the picture is a bit blurred. Poison oak and ivy always have a certain reddish sheen to their leaves and the middle leaf always has a bit of stem showing between where the leaf parts branch and before the leaf parts begin (rachis) and it appears absent in this picture. Might be some sort of anemone...