Viburnum Leaf Beetle Alert!
The Chicago Botanic Garden’s email newsletter is typically informative and sometimes entertaining, but today’s issue bore grim tidings. That is to say, the Viburnum Leaf Beetle (VLB) has now established itself in the Chicago area.
The VLB is originally from Europe but decided to summer in Maine in 1994. Taking up residence, it has been marching westward ever since. It was first spotted in this area in 2009, and sightings have gradually become more numerous. In 2014 there were frequent sightings in a suburb not far from where I live.
There are a quite a few Viburnums in my own garden, so this is worrying news. To make matters worse, a Cornell University entomologist has sorted Virburnum species according to their resistance to VLB. And guess what? Most of mine are Cranberrybush Viburnum (Viburnum opulus var. americana), which are in the “Highly Susceptible” category.
There are also two Blackhaw Viburnums (Viburnum prunifolium – “Moderately Susceptible”) and one Korean Spice Viburnum (Viburnum carlesii), which I planted just last fall. Fortunately the Korean Spice Viburnum is considered resistant to the VLB. Here’s a link to the whole list.
According to a VLB fact sheet put out by Cornell University, the best way to fight this pest is to inspect newer growth for eggs, which look like this.
This is easiest to do before the plants leaf out. Any twigs infested with eggs should be pruned out.
VLB can completely defoliate a shrub, and after this happens for several years in a row the plant will probably die.
As soon as the snow melts I will inspect all my Viburnums for VLB eggs. It’s very aggravating because I just planted several Viburnums over the last couple of years. Some were planted to replace Serviceberry (Amelanchier x grandiflora) killed by bark-chewing rabbits.
Excuse me for a moment, will you? (AAAAAARRRRGH! GAAAAAH!) OK, that’s better.
Anyhow, do you have Viburnums in your garden? Do you have experience with Viburnum Leaf Beetle?