Why are my citrus trees dying?

My piñon trees are dying, help me save them

• They have both pitch mass borer and Ips beetles (http://csfs.colostate.edu/pdfs/pinyon.pdf), and I can either have an arborist inject them with pesticides or spray them. Both arborists I spoke to said their way was the best, but the first costs four times as much as the latter. Has anyone had experience with either of these things? As an aside, we're not going to be living in this house for much more than a year. I'm trying to save the trees because a) It's the right thing to do. b) I don't think a house will sell with dead trees, and c) I kinda feel bad for not noticing how bad I let them get -- health issues, you know. I mention this because I won't be around for long term care. I really just want to get them back on the road to good health. Anyway, we have four huge piñon trees in our front yard which I initially thought were just under watered. But no, they're stressed and have pests. We had a landscaper tell us about the beetles last year and he sprayed them a couple of times, but the arborist I spoke with last week (we've actually had a few come out) said the landscaper sprayed during the wrong time of year to do any good. Now, I'm not an arborist. I know nothing of trees, only that mine are dying. To inject the trees will cost a bit over $1,200 (including pruning). To spray them will cost about $250 - plus pruning in the fall/winter. So I'm leaning towards spraying them. But it hasn't worked in the past, so I'm wary of spraying them. So, my question again is, has anyone had any experience with, if not these particular pests, infested trees, and did you spray or inject your trees? What were the results. I want to act quickly here because my trees are teetering on the brink of no return. Bonus question: We were also advised to get rid of the xeriscaping (rocks and landscape fabric) around the trees and put mulch down since the rocks are probably what stressed the trees out in the first place. Anyone have experience with that?

• Answer:

  Spraying seems to be indicated, and very soon, from this document: http://csfs.colostate.edu/pdfs/pinyon.pdf Spraying makes more sense to me. I'm not a professional. Transport of pesticide in the phloem of a tree that is water-stressed and infested seems a lot more iffy than topical spraying. Bonus answer: water stress probably probably made your pinyons susceptible. Pinyons used to do fine in the naturally xeriscaped areas in the Southwest, until extended drought wiped most of them out (drought, then beetles, then fire), and I don't think mulch is necessary. Just more water.