I have a large (20+ ft tall) sweet bay laurel tree in my backyard. I recently noticed a majority of the leaves have extremely tiny, shiny brown/black bumps on them.

From my research it seems like it may be scale, but I haven't seen any examples online of scale being so tiny. There is also no sticky residue/honeydew present, the bumps only appear on the tops of the leaves (not on undersides or stems), and they are virtually impossible to remove! I've tried scrubbing with a toothbrush, rubbing with a qtip dipped in rubbing alcohol, even soaking a leaf overnight to kill/soften the bumps and then scrub - nothing works. The only thing that does work is scraping them off, but even then they are stuck so hard I often rip the leaf in the process.

If anyone has any idea what these are I would be grateful. If they are scale, then how on earth would I treat them without being able to remove them? I'd like to avoid using anything harsh or systemic as I do use the (non-bumpy) leaves for cooking.

The tree is in zone 8 (Vancouver, BC) and is about 20-25 years old. Thanks!

Bumps can be very hard to see on the dark green leaves: Leaves with minor infestation

This is about as heavy as the infestation gets, most leaves aren't this bad: As heavily infested as the leaves get

Average infested leaf

  • Thanks for the reply! Yes if you have a recipe that would be great. I have tried dish detergent to no avail so hopefully the mixture works to get rid of them. They are very tenacious. – moline Apr 17 at 20:02
  • Interesting, ok good to know, I will try! To bad the dead scale remain, I will be without fresh bay leaves for awhile until enough new leaves grow. But would rather kill the scale than do nothing. Thanks! – moline Apr 27 at 22:05
  • Half cup oil, two tablespoons dishwashing liquid. shake. Then use one tablespoon per litre. – Polypipe Wrangler Apr 29 at 9:12

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