We have Laurels in front of our house that are green and full. We planted...

Asked September 14, 2019, 1:07 PM EDT

We have Laurels in front of our house that are green and full. We planted them a few years ago, and they have been doing well. Yesterday, I noticed that some of the leaves on the side of the laurel had turned completely brown. When I went to go see what the issue was, I noticed that all of the branches of the laurel are covered with what seems to be a white substance. None of the laurels immediately next to this one have the white substance on the branches, but the one two laurels down has the beginnings of it. I’m not sure what this is or what to do about it. I’ve attached some photos.

Montgomery County Maryland shrubs white prunicola scale pest insects and mites

1 Response

Hi - The white coating on the branches is an infestation of white prunicola scale. They are insects that feed on the plant sap. This causes leaf yellowing, leaf drop, and branch dieback. This insect is difficult to control and we recommend removing the heavily infested shrubs.

If you want to try to manage it, you can brush off the scale with a soft brush. When the plant is dormant, (look at other deciduous plants and see when they drop their foliage) you can spray with a dormant horticultural oil. Follow all label directions. This may help to reduce the population, however, you will have to monitor the plants next spring. If you see crawlers (juvenile scale insects) in June, you can spray with a summer rate of horticultural oil. You may decide to remove the shrub and plant another type of plant if you cannot get control.

This scale is a preferred host of Prunus, flowering cherry, lilac, and privet.
Take a look at our blog on cherry laurel and how to grow this plant in your landscape. https://marylandgrows.umd.edu/2019/01/07/qa-whats-wrong-with-my-cherry-laurel-shrubs/

Christa