With the information given, I'm unsure what happened to the tree, but... "Last year we started up with a tree service that does insect sprays and root injection fertilizing." Sounds like possibly a real racket! Insects aren't usually a problem for healthy trees. What kinds of insect problems have you had? As for the fertilizing, what nutrients was your soil missing? Applying the needed nutrients to the surface would probably be much more effective than the injection method. I could be wrong, but it sounds like they saw you coming!

I assume you've checked it for visible insects like leafminers and scale? A few other possibilities spring to mind: Cold damage. If the leaves were touched by a frost after they emerged they will wilt, usually blackening and dropping too. Mice could have chewed into the bark and branches over the winter. Pull back any mulch you have and examine the base of the branches for chewing damage. Keep mulch away from the base to discourage them. A bacterial blight caused by Pseudomonas syringae. It causes brownish wet-looking spots to appear first. New shoots and leaves will then blacken and wilt. You have to prune all affected shoots as soon as you notice the symptoms (dip pruners in a 10% bleach solution between cuts). Lilac borers will affect leaves and branches. Look for small holes (about 2-3mm in diameter) near the base of affected branches - sometimes you can see sawdust. Bend the branches that have wilting leaves - if they're brittle and break, that's almost certainly your problem. Lilac borer damage usually becomes visible towards the middle or end of the summer, but if you had a bad infestation last year, some branches could be gasping their last gasp now. Other possibilities are damage from a mower or herbicides. In general, I would advise against treating any plant with any kind of instant fix solution if you have not identified the problem. I've had several friends kill sick plants by fertilizing them, thinking "it can't hurt", when it did - the plant died because of the additional stress placed on it. Identify first, treat second :-) BP

Seems like everyone has given up on this, but in my opinion, the roots have been smothered. Since all of the leaves are drooping but don't seem to be damaged, it isn't a pest. 80% of the time shrubs are planted too deep and while it may take two or three years to debilitate the plant, it's inevitable doom. Oxygen can't get to the roots and the plant slowly suffocates. Fortunately, Lilacs are deciduous so during their dormant period you can replant them higher -- about two inches higher than level grade. It won't hurt to cut the branches back about 1/3 at the same time. Once replanted, water deeply twice a week.

No, PM will not make you sick. There are a zillion particles that come in through window screens and those who suffer from severe allergies usually keep the windows closed. If you've never been bothered yet, PM won't give you any problem.