Bee? Wasp? Hornet? What to do with old lilac?

[Hooverville]

So we have this really old lilac growing in the southeast corner of the property. It's not the greatest, the limbs are covered with some sort of white/blue colored fungus; and when we pruned it, we noticed that most of the limbs were actually hollow. Obviously, something has infested it. Anyway, yesterday I noticed at the very base of it, there were swarms of bee-like creatures covering it and a large number of flies. I tried looking it up, but apparently you have to get close enough to see exactly if it's a bee, wasp, hornet, or whatever. And with my eyesight, forget it! Honeybees would be ok with me, but I am thinking it's highly unlikely that's what they are. So my question is, what to do? Do I wait till spring, or do I need to eliminate them now?

[Dame]

I would think it is likely ground bees.

Lilacs renovate nicely if you cut them off at the ground and then let them regrow. Ours take a couple of years to be looking like young vigorous bushes.

[momma_to_seven_chi]

I would just cut it off and let it regrow too. I wouldn't get rid of it or dig it up or anything.
You might also just get some of the Bayer stuff to put a few drops around it. Imidacloprid kills bugs quite well, but it is a pesticide.

[Hooverville]

Thanks for the advice - not sure if we want the lilac there anyway, so I guess we'll wait til spring to decide.

[Mad_Professor]

If you don't mow around it many new lilac will sprout up from the seeds , that can be transpanted

[cubcadet]

Lilacs are very expensive to buy at nurseries because they`re very slow to get established. I would not destroy it. Once they`re going good and producing lots of blooms, it`s very difficult to prune. It is best to prune on a 3-5 year cycle. Remove 1/3-1/5th of the old growth in a given season, waiting until the blossoms begin wilting. First deadhead the blossoms to prevent it from trying to produce seed. Remove old growth to the soilline. This forces it to produce root grafts. Then remove inward growing, dead or otherwise unhealthy branches. Next year at same time, remove another 1/3-1/5th old growth and so on every summer until there remains only new topgrowth. You will have an essentially new shrub at that time. Good luck.

[Junie]

The bees sound like they might be yellowjackets.

[Under_The_Moon(]

I think they might be yellow jackets too. They nest in the ground most of the time and tend to hover around the area then disturbed. If you put some ammonia in cup and place it under the tree for a week they will leave.