Bay Tree

May 26, 2009

Bay Leaves

Dear Diana,
I have a beautiful Bay leaf tree in my garden and about 6 months ago, I noticed white crusty scales growing underneath some of the leaves. I took the leaf to a local nursery and they told me to spray the tree with a mixture of detergent and water. The scaly growth has become worst and sometimes I see white, web like material growing in patches. I normally trim off the branches that have them and the disease doesn’t reappear for quite some time.
Can you shed some light on possible cures for this plant disease?
Thank you.
Dee, Costa Mesa, Ca

Hi Dee,
For once I can say "I'm glad you asked me that" since I recently had a conversation with my daughter about the same problem - and the solution is simple and easy to do. What your Bay is suffering from is scale, which is a problem with Bay trees and with some woody stemmed houseplants.
Actually each scale is a non moving insect which latches on to the plant and sucks the sap from it. In the main, if the shrub or houseplant is healthy it will withstand a scale infestation, but it's not attractive and doesn't do the plant any good. In England we have an alcohol called methylated spirits - in the States it is rubbing alcohol, I believe - and you just soak a cotton bud in this and rub it well onto the patches of scale which will then over a day or so, dry up and drop off.
If there is a largish patch of insects you can use a small piece of cotton wool, but try not to get it on the stem of the plant as it is very drying. You may have to do this from time to time, but it should be effective.
The white, web like material could be a different pest called mealy bug, which is treated the same way.
If you use Bay leaves in your cooking you might or might not know that Sweet Bay is one of the few herbs that is better for being stored, as the leaves straight from the plant are agreeable, but a handful of leaves thoroughly dried and carefully stored for future use have a much better concentrated flavor.
Do remember to use sweet bay as opposed to common bay or laurel for cooking.
As Always
Happy Horticulture