Bay tree - leaves going brown

[haggis]

I have a lovely bay tree in a pot in the garden. I use the leaves for cooking but at the end of last year the leaves started to get black spots - which then spread. Once the leaves are heavily infected they go brown and die.


Does anyone have any ideas as to what this is? Is there any way I can treat it and still use the leaves?

Thanks

Haggis

[Beccy]

I would start by checking for scale insect, which look like little scales ( )up to 3mm long, laid tight to the leaves and stems, often against the veins of the leaves. They excrete lots of honeydew which covers the leaves (are/have they been at all sticky?) and provides food for the mould which is probably what is causing the black spots.

If this is the problem rub the scale insects off, give the leaves a clean and it should recover. You need to keep an eye out for more scale insects and it may be worth moving the pot as apparently ants sometimes 'farm' the scale insects and will just keep putting more on if you remove them.

This has happened to my potted bays and they have recovered very well. It does take a while to check all of the leaves for the scales, but it can be done while relaxing in the sun.

[Jude]

I have the same trouble with my bay - scale insect then consequent sooty mildew. Rubbing off the scales helps, but I've found that re-potting, into a larger tub, or just with scraping out and replacing the top third or so, seems to give the plant a real boost and reduces the stress on it. That's if you can do it. The first time I did mine I found it was so root-bound it was a really tough job!