Cherry laurel branch stipples

Asked June 20, 2016, 12:12 PM EDT

My cherry laurel bushes planted last fall have developed white stippling on some of their inner branches. What is the cause of this and how can it be treated? Is this something that I should present as a warranty matter for the landscape company? I include pictures of the stippling, the entire bush, and one of the many leaves that have fallen from the bush. Thank you for your help.

Anne Arundel County Maryland shrubs cherry laurel white prunicola scale

1 Response

In general when shrubs are stressed due to poor planting tecniques, poor site conditions, and environmental issues, they can bae susceptible to insect and disease issues.
The white spots on the trunk looks like white prunicola scale, a sucking insect. This insect sucks plant cell contents from twigs and branches. This can cause dieback, which is usually preceded by leaf yellowing and premature leaf drop. If the other shrubs are stressed, they can be susceptible to the scale. If you have a warranty, check out the specifics, and you will have to decide.

Make sure the shrubs are not planted too deeply. Deep planting causes bark deterioration at the soil line which will eventually kill the plant. Cherry laurels grow best in partial shade in a well drained soil. Check the drainage in the area (they do not like wet soils and poor drainage), make sure mulch is no thicker than two inches in depth, and keep away from the base of the shrub. Boring insects can be attracted to excessive mulch around the base of plants.

Here is some information on control. If the infestation is light, Prune out any dead or dying branches. You can scrub off the white scales with a soft brush.
You will have to check for crawlers starting in May (there may be three generations and they are salmon colored) before you spray. Wrap some of the branches with double-sided sticky tape to monitor for crawlers. When you see the crawlers, spray with a summer rate of horticultural oil. Follow all label directions. Do not spray when temperatures are in the high '80s in hot weather. https://extension.umd.edu/hgic/armored-and-soft-scales-trees-and-shrubs
mh