Subject: Large wasp
Location: Gaithersburg MD
August 5, 2012 1:42 pm
I live in MD and have a lilac bush that is now covered with what appear to be giant wasps. There is ”saw” dust at the base of the tree, there is a sweet odor, and there seems to be several dead limbs now on my bush. The wasps seem to be eating into the tree and are about 2 inches long. They are congregated at the base and several limb joints.
Signature: Vandy

Cicada Killer

Hi Vandy,
These are Cicada Killers and though they are feeding on the sap produced by the lilac bush, we do not believe they are responsible for the poor health of the plant.  The sawdust and dead limbs are most likely due to some other cause.  Perhaps some other insect is compromising the health of the lilac shrub, and the result is the sweet smelling sap that the Cicada Killers are feeding upon.  Cicada Killer females prey on Cicadas to feed their broods which are found in subterranean nests.  Cicada Killers are solitary wasps, and despite their large size, and their habit of defending territory, Cicada Killers are not prone to stinging humans.

Location: Maryland

4 Responses to Cicada Killer eats sap from Lilac bush

  1. Keith says:

    I began pruning my over grown lilac bush, when these huge wasps/hornets starting buzzing me. Same scenario as original question; dead limbs, saw dust, etc. In fact I am not far from Gaithersburg. They were scary but didn’t seem hyper aggressive as wasps defending a nest. I’m confused because all the info on these critters say solitary, yet I had a bunch of them flying around

    • bugman says:

      When Wasps are considered Solitary, it means they do not have a communal nest, however, there might be colonies near good nesting sites with each female tending to her own brood.

  2. Roberta Pipitone says:

    I am in Western North Carolina. I am seeing the same thing. My lilac bush is covered in these things and the leaves are curling, as though dying. I cannot see the base of the tree, as it is surrounded by a low bush.
    The tree was very healthy before this invasion!

    • Keith says:

      I thought the same thing. I never really noticed the wasps until I started pruning the lilac bush, then they were everywhere, seemingly trying to run me off. Then I learned I can ignore them (VERY difficult to do) and go about pruning and we each mind our business.
      As I pruned and cut out dead sections, I started seeing ants. Then more ants. The very dead sections were hollow in the middle and full of ants. I ended up cutting down the whole bush. It will grow back in a few years.
      Going forward I will keep it pruned to 5 or 6 feet in height. Lilacs are pruned immediately after flowers die, as they start setting buds for the next year very soon after flowering.
      If you work your way through the lower bush and see saw dust, that is the work of ants, not these wasps.

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