My indoor lemon tree has scale bugs. I washed them off with insecticidal soap, scraped off the scale (used an old electric toothbrush) and rinsed the tree off and sprayed the tree with alcohol. Do think the stems where the leaves fell off will come back or do I have to trim the naked stems off? Will I have to retreat the plant?
It sounds as if you were pretty thorough in treating your lemon tree for scale pests, so at this point I would hold off on any trimming or pruning to give your tree time to regenerate and recuperate from the pests and the consequent cleansing. As for retreating the plant - a re-occurrence of scale pests is in the realm of possibility. I would advise keeping a close eye on your lemon tree for awhile to be sure you eradicated them and remove any new scales you see.
For more information on controlling scale pests, please visit the following link: