Lilacs getting chewed

Asked September 13, 2019, 12:49 PM EDT

Attached please find photos taken July 2017, which I sent to your team for diagnosis. At that time the diagnosis returned indicated leafcutter bee. I have three lilacs in my backyard and they have now all been invaded by a chewing insect. I did observe some beetles at night, and from photos I've seen on the internet it appears to be some kind of root weevil. The bushes are alive, with very few dying branches, but they produce fewer leaves and flowers each year. The lilacs are located under the canopy of an Emerald Maple that filters out much direct sunlight. They were all planted together with the Maple 21 years ago, and they have been very healthy and robust until the past few years. I would hate to lose them. Can you suggest an aggressive detailed treatment, as it has now spread to all my lilacs? Is there a service you recommend for ongoing treatment if needed?

Douglas County Colorado

1 Response

The article below is about why lilac shrubs don’t do as well in some years or after a while.

Lilacs like a lot of sun for one thing and the Emerald Maple might be the reason they are not getting the sun they need to bloom.

https://planttalk.colostate.edu/topics/trees-shrubs-vines/1729-renewing-shrubs/

The photos you sent do look similar to the photos describing the Root Weevils damage in the publication below:

https://extension.colostate.edu/topic-areas/insects/root-weevils-5-551/

To be certain perhaps a certified arborist can come and tell you for certain.

Below is a web pace where you can locate one of those:

https://isarmc.org/content.php?page=Public_Resources