Thanks for the replies. But there's nothing good to report, I'm afraid, on this tree.
I did try the foliar spray, tho on Al Keppler's suggestion I used a weak solution of water and molasses. (Lots more goodies in molasses. Really got the interest of the Hymenoptera
insects, I'll say that.) But it appears to have been too little, too late. No healthy needles are left, at all. Browning and dying started at the needle base, all over the tree, which indicates serious root damage.
Thinking back, I remembered that the "tired" look to the needles was there last fall. We had unusual drought last summer, and I was sometimes hard pressed to keep everything watered. I remember one time in particular when I was in a hurry for something and let this tree wait an extra day for water, thinking, "Pondys are known for their drought resistance."
I talked to Andy Smith in Chicago, and he thought my guess was probably right. He told me, too, that he lost about a dozen trees after last summer's heat and drought, and now thinks he didn't adjust his watering in time. At least I didn't feel entirely alone!