Georgia, Definitely spider mites. I have never tried the fish emulsion, although many here sing its merits. I use ultra fine horticultural oil. I mix up a small sprayer (24 oz, I think) with a 1/4 teaspoon of the oil and warm water, shake, spray all surfaces, crevices, branches, trunk and top of soil. The bottle will have the exact dilution requirement. Do it in the morning or at night, in bathtub if the weather is not cooperating. With this degree of infestation, I would repeat in 5 to 7 days, and repeat one additional time if necessary. It is organic, smothers the mite in the adult and nymph stage, but is not as thorough on the eggs, thus the repeat(s). The one advantage for this time of year is it does not smell like fish emulsion will. Doing this once a week in the fall starting about 3 weeks before you plan on bringing them in will cut down on your infestation. Once or twice in the winter if you see signs would help your tree rebound sooner in the spring. They are sapping the energy from your tree. Good luck. Barb

I don't believe the "not improved" form would be available for sale in California. The only difference is the presence or absence of citrus tristeza virus infection. It causes no symptoms at all in the 'Meyer', so the two look and act exactly alike. The problem is that the virus can spread from an infected tree to oranges, grapefruit, and other citrus nearby (spread by aphids) if you have an infected tree. I suspect your nursery bought their trees from two sources, one of which used the term "improved" while the other did not. It used to be, and I assume still is, illegal to sell the infected form in California.

OK, you're feeding it a lot, so let that rest for a while. You don't mention citrus fertilizer and iron, both of which are needed for citrus in the ground. Like roses, they're hungry all the time and will exhaust the soil during their extremely long lives. I feed once every month or two with citrus fertilizer, liquid iron at least twice a year. I save the liquid fish/kelp dousing for no more than once or twice a year, but always after the main harvest ends - right around the end of this month or so. The new growth will always tell you how well the citrus is doing. If it's dark green, it's getting enough food. If it's unfolding a paler green, the plant is hungry. I mulch with either mini-bark or cocoa hull mulch, which seems to work better for me in conserving moisture than compost. I can't find any info on meyers specifically, but according to one web source, 40 yrs is about the average lifespan of a lemon tree, with production dropping off as it ages although it may live longer.

The first place to look, in your job as plant detective, is the potting mix. Is it very coarse textured and fast-draining? Most commercial potting mediums are almost entirely peat, which can make them sludgy over a bit of time. Those potting mixes can cause over watering issues, as well as develop dry pockets from improper watering (little sips at a time).