Editor’s note: this is part two of this series. Don’t miss part one of Viburnum Under Siege.
The accidentally introduced pest, viburnum leaf beetle (Pyrrhalta viburni) or VLB for short, can destroy a shrub in just a couple of years. Unfortunately it continues to spread through North America. So I am trying to learn more about it, hoping that we can protect the viburnums in our area. This is the information that I have gathered from the sites listed and from my own observations. It doesn’t look very encouraging.
The grubs or larvae emerge from eggs early in the spring. They are yellowish or greenish, with black markings and can reach one third or a quarter of an inch in length.
They spend a few weeks feeding on the leaves by making numerous little holes between the veins. These holes are easy to identify. By early or mid June they climb down along the stems and bury themselves in the ground to pupate. When I searched for them in mid June, I found none, only the damage remained.