Viburnum Borers
By Dr. Don Booth

There are two clearwing borers that are becoming more common as viburnums are used more frequently in the landscape:
1. Viburnum borer
2. Lesser viburnum borer

Facts on the viburnum borers:
Both species attack the root collar and lower stems of viburnum. Caterpillars tunnel under the bark, eating the cambium, and eventually enter the wood. These are not rapid plant killers- we usually have several years to detect and treat before plants die.

Eggs are laid near wounds on the bark during June through August. Viburnums planted too deeply are at greatest risk. Plants shipped out of nurseries may already be infested.
Adult moths are captured in the standard clearwing borer traps, but look similar to lesser peachtree borer.

Control viburnum borers with preventative bark sprays using Baseline (12 oz./100).
Treat twice each year: early June and July. A key to control is root collar excavation prior to spraying.

Arrowwood viburnum is the only species with resistance.