Q.Meyer Lemon Indoor Tree Pest
Hello, I have had a Meyer lemon tree for several years. The tree produces lots of fruit but over the last couple of winters the leaves fall off even though flowers appear! Recently thiugh I have noticed a sticky substance on the branches, the fruit and the table is sits on. I took a damp cotton bud and wiped it over which brought off what I think was scale bugs. They were on every branch so I have wiped over to remove them. I noticed on one of the leaves there was quite a collection of them so I’m hopeful they have been eradicated but I might have missed some. Because I am not totally sure the best way to treat this as I might have identified the pests wrongly and I would appreciate a bit of advice please. I do have a photo of some that I took off the plant and attach this for you. I am loathe to spray with a pesticide as many years ago when I had aphids on an orange tree I was advised at our local garden centre to use a spray for some reason seem to affect the tree and it never fruited again. This tree lives outside now and only ever grows leaves. If it is these scaly bugs I have read that you can spray the plant with an oil but it sure how effective it is and would be grateful for your advice going forward.

Certified GKH Gardening Expert
It could be scale but they are usually hard to remove. Scale and aphids will leave the honeydew sap you are finding. Spray the plant with Neem oil, on the top and bottom of the leaves as well as the stems. You may have to reapply in about a week.
https://www.gardeningknowhow.com/edible/fruits/lemons/growing-meyer-lemons.htm