Viburnum Mohican “pests”

(Question)

I have two mature viburnum bushes in my backyard and every year the leaves are being eaten by small grey-ish insects (a bit smaller than a maggot) and the leaves are turned into “skeletons”. I have done some research and found out that those insects are “surviving” the winter by laying eggs and “living inside the plant” – creating little cavities in the centre of a branch/ twig. I have thinned out the bush and trimmed part of it but they keep coming back. what can I use to successfully eliminate them and have full and luscious bush? Thank you in advance for your help and advice.

(Answer)

Thank you for contacting Toronto Master Gardeners regarding your ailing Viburnum lantana ‘Mohican’, also known as Wayfaringtree viburnum, a species susceptible to the viburnum beetle.

The Morton Arboretum has an excellent post describing the beetle and its metamorphosis, found here:

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-pests/viburnum-leaf-beetle

The University of Maryland Extension also provides a description and management strategies to control this pest. https://extension.umd.edu/hgic/viburnum-leaf-beetle

as well as providing information and photographs to identify the beetle’s various stages here: https://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/ipmnet/VLB%20Field%20ID%20Guide-UMD.pdf

We wish you well in getting this pest under control.