Question
Hello, I have a 4 foot Meyer Lemon that battled a very frusturating scale infestation last summer (the soft, tan and black spotted ones). I managed to rid the plant of them by tediously scrubbing with isopropyl alcohol, but it has yet to bounce back, and lost 60 percent of its leaves with no new growth. Recently, I noticed some new scales that were starting to spread on it again, and removed all that I could see. the thing is, at the time it was first infested, it was developing fruit, which did not drop off, despite the leaf loss. I did not pick the baby lemons off, and let them mature until they were ripe enough to be eaten. Now that the tree is fruit free, will it bounce back? if so, how can I help it along? I gave it a light fertlilizing with fish emulsion, but it did not seem to help, and it is too cold to move outside right now.

Answer
Hi Emily,

The very, very best advice I can give you is to try to maintain the scale insect population until you can move the plant outdoors.  ALL plants require sunlight to produce the necessary products (proteins, lipids, and other cell components)for active growth.  Though our environments seem adequately lit for our eyes, the plants are, relatively speaking, in the equivalent of a cave with respect to light.  While the nutrient manufacturers insist that fertilizers are necessary for plant growth, and they insist that feedings be conducted year round, without sunlight, the plants do not use the fertilizers provided.  

Once you place the plant outdoors, the natural predators will take care of the scale insect population, especially if you are in an area that has active gardening or has abundant landscaping that can support a thriving insect population.  Ladybird beetles are especially useful as biological controls of scale insect infestation.

For the time being, be patient.  You are doing the right things, and you shouldn't worry that the plant is not putting on any new growth.  That will happen when the plant is in a better light environment.  Also, if you are concerned that the defoliated branches may be harmed, there are dormant buds at each node that can sprout new leaves.  

Remember, though, when moving plants into a higher light environment, use caution as the plants need to develop more chlorophyll and accessory pigments to handle the higher energy provided by the stronger sunlight.  First place the plant into a shaded position for about one week, and then gradually move into full sun.