Bill, have you found out what these spots or plaques are on the undersides of your leaves?

Patty S.

They look like eggs; and likely should be cleaned off before they hatch... Send the photo by email to Rhizo on this forum; she can probably tell you more.

Believe me, I've been looking. Since wjell could not remove the 'spots', I don't believe them to be eggs of any kind. I'm going to suggest that these might be the eruptions of edema, not unheard of on container grown plants.

Edema appears ad small bumps, blisters, or warts on the underside of the leaves. It can be an indication of a potting medium kept too moist for too long, or other environmental factors relating to moisture.

If your tree is of finite size, just rub them off with your finger. They will not be able to climb back up in the tree. Once you try this idea you will be surprised at how big of a tree you can hand comb. This works for most pests.

These don't look like a scale species, ponci.

I think what I have on the undersides of the leaves of my potted meyer lemon is the same. Has anyone correctly identified these? And does any one know how to get rid of it? The leaves are curling where these are present.

That looks more like spider mites.

Yeah, those are definitely spider mites. If you have access to a hose, spray the undersides of leaves with jets of water. If not, then use "neem oil" once every two days for 5-7 applications when the temps are below 85*F.

-Tom