Sick or Dying Lilac?

I'm worried about our lilac. I'm not sure specifically what it is or how old it is. I just know that it looked great up until summer. About that same time, the horrific plague of 13 year cicadas was at its peak and I just figured that had something to do with it. Now I'm not so sure. It looks pretty rough. There are parts where it looks like the dead of winter. Most of the bottom has no leaves and all of the mid-section leaves have nasty brown spots. Today, I discovered some sort of beetle gathering on the bark in the middle. What's going on here? After taking some pictures, I knocked off the beetles. It appears the wood beneath them is damaged. IS there anything I can do to save it? Should I spray something and/or cut out the infested areas? HELP!!!

Another view. See how thin and dead everything looks at the bottom/middle?

The yucky brown spots that are everywhere.

The infestation of some sort of beetle!

And the yuck beetles' damage. I do find it somewhat comforting that there does seem to be new growth in small areas. After the infestation is treated, would it benefit from being trimmed back a good bit?

Wow. The good news is I don't think you can kill a lilac. At least it's really hard to! The brown spots are just rust, I believe, not a big deal and not related to what else is wrong. You might want to catch one of those dudes and compare it to beetle pictures. They do seem to be the culprit in the bark damage OR they're moving in because the shrub is weakened by a systemic fungal disease. I hate to say the word verticillium because I just dealt with it's hearbreak, but take a twig that is sick and prune it off. Look inside the pithy stuff in the twig and if there's a brownish dot in the center, it's likely fungal. Not good.

I could be wrong but I don't think the brown spots are rust--here are some pics of rust for comparsion: http://www.dgsgardening.btinternet.co.uk/rust.htm Rust also tends to only affect certain types of plants, and I don't believe that lilac is one of the ones that is typically susceptible to it.

Ecrane, thanks for reminding me not to carelessly throw out words, like "rust". While I've always used "rust" to describe leaf spots because it's so very common, it IS a specific organism and even specific to plant species.

Most of our leaves have spots by this time in the growing season, though, because there are so incredibly many fungal, bacterial, viral and what-have-you organisms, not to mention insects, wind, rain, hail . . . whew! Anyway, it is some sort of leaf spot (which, I think, is also a specific organism, as generic as it sounds!). Here's a link showing spots on lilac leaves: http://blog.lib.umn.edu/efans/ygnews/2010/07/bacterial-blight-blacken-lilac.html. Don't let the word "blight" scare you. I really think leaf infections are not a huge deal and are strictly an aesthetic issue for the growing season.

The bark, though, is worriesome . . . would definitely check that out.

This message was edited Sep 27, 2011 6:50 PM

Oh, for heaven's sake, the link doesn't work! I just looked at the page! Here, I'll try again: http://blog.lib.umn.edu/efans/ygnews/2010/07/bacterial-blight-blacken-lilac.html If it doesn't work, I'm sorry. Maybe you can just Google "brown spots on lilac leaves" - that's what I did.