Well, if you could post a photo, you would get a lot better advice; but short of that you have probably made some of the classic Meyer lemon errors. First, when you dramatically change the light conditions a Meyer will drop most, if not all its leaves, to replace them later with leaves better suited to the new light conditions. To move a Meyer from outside to inside without the leaf loss, you need to move it from full sun to partial sun for 2 weeks; then to full shade for 2 weeks; then indoors; reverse the process when putting it out in the Spring... and please DO put it out, if you can; you will be rewarded with a happy, healthy plant.
Second, when you bring it indoors to a sunny window, the plant gets warm; but the roots generally stay cool; and citrus roots don't like to grow into cool soil... the solution is to put some sort of heater to warm the soil, or to put the plant a little further from the window. The thing to remember is first the roots grow; and then the leaves and branches.
Now to your current situation... the plant is stressed and "thinks" it is going to die, so it is making seeds (fruit). If you take off the flowers, the tree will only make more; so wait until the flowers drop and then take off all the fruit; soon after that, if you treat it well, it will start to make new leaves... and then you should start to feed it. Have patience,

A picture of the tree is posted. To be clear, the lighting and temperature conditions have not changed. I have moved the tree from one sunny balcony to another. The tree also stays outside year round as Hawaii doesn't have dramatic winter/spring seasonal changes. My question was referring to the street grime and soil possibly causing stress on the tree.

Aloha,

We've been having a bout of really wet weather. The residue may not be street grime but sooty mold. Could be from insect attack. Couple of the leaves look curled. Check for insects or eggs. There are plenty psyllids around nowadays. If so given the extent of damage, I am sorry to say that you may have to spray with insecticide.

Thank you so much for telling me about the sooty mold!!! I haven't thought of that. It looks exactly like what has been collecting on my lemon tree.

I had a problem with scales on this lemon tree last year which I got rid of using diluted fish emulsion spray. I may have similar problem this time around.

Yes, you have a combination of things going on..

The light is not an issue since you said that has not changed, but I tend to think it's that mix..

It looks a little to wet fine, peaty for my trees and that alone can cause severe issues.. It looks like it has had its day, worn out. It has lost its structure and porousity..That alone can be certain death because of reasons I mention here.

It can collect salt residue from fertilizing and tap water if you do not flush once a month and fine roots killed off from those salts can cause your tree to starve for fertilizer and or water..
Root rot can also cause this effect..

Which is why I also question whether you have pests or no,t since they are attracted to trees that are rich in sugars and defficient on hydration..

If it were me, I would either flush the mix and keep an eye on how long it takes for your pot to dry out right down to the root zone..
I would also check the root zone to see if it has suffered any root loss which that is a symptom.

If the roots are still healthy and the soil works like it is suppose to, then flush the heck out of that mix with fresh water and the fertilize on a regular basis..

If that soil is not doing the proper job, then I would use a very fresh porous mix, rinsing all the old soil mix of those roots.. I would wait about 2 weeks before fertilizing again in this case.I would do a repot a.s.a.p if it needed it after examing every thing and you see a need.

It looks like it's in need of some much needed food, for sure to support good growth in all areas, once you make sure the roots and mix are ok..

Good luck!

MIke

This post was edited by meyermike_1micha on Mon, Mar 10, 14 at 19:58

You're quite welcome Aeslehc! By the way, MeyerMike is right. There are some serious issues. Some of the leaves have chlorosis where you can see green veins on a yellow background. There are some nutritional issues going on. Couple of the leaves also have bite marks. The psyllids look like scale when immature and I had gotten some on my last purchase from that local grower (looking at the tag). You would have to use something stronger than fish emulsion. Would recommend spraying the tree till dripping wet with neem or bayer. Give it a week at its current spot for the insecticide to dry and work. Then try to move it out to an outdoor spot if you can. Water. When the new leaves come out, respray. Then fertilize. Then repot.

Thanks for all the suggestions! I will definitely have to spray with insecticide because it does look like immature psyllids. It was hard to see until I knew what I was looking for. The bites are from a new Swallowtail which I have just relocated to another citrus tree. The roots seem ok just below the soil but I must've drowned the tree with watering because the rain and humidity have also been high lately, making matters worse. I think I will allow it do dry out and go back to doing infrequent deep soaks, give it some food and repot with better draining soil. Thanks again All!

This post was edited by Aeslehc on Wed, Mar 12, 14 at 3:51