I have 12 year old cherry laurels in my front garden that have been very...
I have 12 year old cherry laurels in my front garden that have been very healthy until I just noticed large branches of brown leaves and a type of white mold all over the branches. I don't see any mold on the leaves, just the branches. The leaves seem to be green and healthy, yellow or just brown and dead, nothing in between I'm concerned that this will spread and destroy all 6 of my well established bushes. I want to identify the issue and determine how/if I can control it.
From your photos it looks like white prunicola scale on the cherry laurels branches. This is a sucking insect that sucks plant cell contents from twigs and branches. This can cause dieback, which is usually preceded by leaf yellowing and premature leaf drop.
Here is some information on control. Prune out any dead or dying branches.
Now you can use a soft brush to remove. You will have to check for crawlers (there may be several generations and they are salmon colored) before you can 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 eighties in hot weather.
You can use a dormant oil to manage light infestations in the fall when trees drop their foliage. As long as it does not freeze within 24 hours.
Thanks for the information. The problem is pretty wide spread so brushing off the branches may be an entire day project. I'll have to suck it up and just dive in if I want to save my entire set of bushes in the front. Wish me luck!