I bought a small lemon tree last summer and planted it in a pot on my patio. When the temperature went below 50 at night, I brought it inside. After a while it started dropping leaves, a few every day. I thought it was just the change in location. Then I thought it needed more light, so I brought it into the guest room, which is really light and airy. But it's still happening. I saw on a website that it might have leaf miners. I followed the link to your website. But your description of leaf miners isn't what the other website described. It said "Citrus leaf miners are also an intrepid pest assailing lemon tree leaves. Barely noticeable to the naked eye, leaf miners are not easy to control with chemicals since they are burrowed into their dens between leaf and stem. Infected areas of the tree should be removed and destroyed to aid in management of the insects." So now I don't know if I should treat the little tree or cut off the section before it spreads. Help!!
Lemon Tree Dropping Leaves
Certified GKH Gardening Expert
Lack of sunlight, temperature fluctuations, lack of humidity, and watering issues could be the cause of the leaf drop.
It can be difficult to give an indoor citrus tree enough sunlight, especially in the winter months, without adding some artificial light.
Here are some links to refresh you on the care requirements.
If you still suspect insects or disease, Neem Oil can be used as a safe treatment.