Help identifying pests on Meyer lemon tree

Hello. Beginner fruit tree owner here- I just moved to a property with a small Meyer lemon tree, about 2-3 ft tall. It has these small brown scales (~1-2 mm diameter) on the leaves that won’t come off, and a lot of the leaves are half eaten as shown in the photo. Does anyone know what this is, or what I can do about it to help the tree? I heard of neem oil and diatomaceous earth, but I’m not sure. I’m in zone 10a, Big Sur CA. Thank you!

scale bug

Horrible pests.

The ants put them on my trees when they are outside in the summer.

Emily Hart wrote:Hello. Beginner fruit tree owner here- I just moved to a property with a small Meyer lemon tree, about 2-3 ft tall. It has these small brown scales (~1-2 mm diameter) on the leaves that won’t come off, and a lot of the leaves are half eaten as shown in the photo. Does anyone know what this is, or what I can do about it to help the tree? I heard of neem oil and diatomaceous earth, but I’m not sure. I’m in zone 10a, Big Sur CA. Thank you!

The scales are a sap-sucking insect (scale insects), and neem oil will not do much for those. I think using a horticultural oil to coat the trees will help to suffocate them. You can also spray with soap and use a rag to crush and wipe them off, but that's a lot of work. I edited this response because apparently this forum does not allow the mention of chemical options (I have no idea what "natural" compounds are OK to mention? Maybe I'm allowed to suggest the use of essential oils, even though some of those are also dangerous and toxic?). I never use any of that stuff myself, regardless of whether the chemistry is done in human factories or plant cells.

The missing chunks of leaves are some other pest, maybe some kind of caterpillar, possibly earwigs? Could be many things, but it's not the scale insects.