Leaf damage show signs citrus leaf miner. They wont kill established tree like yours but you can control the pest with insecticide, spasinod (spelling)

The biggest problem is you are not fertilizing enough; the fertilizer spikes are virtually worthless for citrus, which are heavy feeders. Get some good granular citrus fertilizer and apply it at least 3 times per year at the dripline of the tree according to label recommendations. It is also likely you are under watering the tree, as it is unlikely a drip system is enough for your tree in Palm Springs. Water about once a week with a hose left to soak deeply; the soil needs to be wet at least 18 inches deep, the area where citrus gets about 85% of its food. Another good idea, because you have desert soil, likely with a high pH is to get some good quality chelated minerals including Iron, Zinc, Calcium, Copper, Magnesium, Manganese and put that also at the drip line and water in well.

The leaf damage, as mentioned above is mostly citrus leaf miner and maybe some omnivorous leaf roller; both are cosmetic, but can be controlled beginning at the first flush of new growth before the CLM population gets too large.

You've likely missed the primary bloom this year for oranges; but if you do these things you should get a good crop next year.

+1, use granules slow release fertilizer and spread it around under the canopy. make sure you use citrus specific fertilizer which as mentioned above will have essential minor elements.

The problem with that is that the essential minor elements in a commercial citrus fertilizer will not all be available to the plant in high pH soils, i.e. over 7.5; in those cases you have to use chelated minerals to be effective. For my field trees I do an annual application of chelated minerals; my soils don't really demand chelated and they are a bit costly; but for me it is cheap insurance, if you want to be sure to get a good crop. The other issue is slow release is costly, often less effective, and basically unnecessary for inground trees; it may make some sense for container plants; but if you want to use slow release, it might be better to just put a diluted fertilizer with every watering... often referred to as weakly weekly.

John. If your growing using compost and organic fertilizers that "weakly weekly" method does more harm than good to the beneficial bacteria in the soil. I would suggest a slow release organic fertilizer and, if you need to, an organic liquid micro formula. Also if your soil Ph is too high OM and elemental sulfur will eventually bring your Ph under control. Its the use of chemical fertilizers (ie Miracle Grow and the like) that over time depletes your soil of anything organic (including earthworms, mychorrizae and beneficial bacteria) eventually the only thing that helps your plants is the "weakly weekly" method because your plants become so dependent on the chemical fertilizer due to having nothing of substance in the soil. I used to use chelated fertilizer in my soil until I began reading the soil forum. The good thing about organic gardening is once you get your soil established you rarely have to feed your trees as most of the nutrients your trees need is in the soil.

The only time I use liquid soluble non organic fertilizer is in my containers and pots. For my in ground trees I have begun a schedule of using compost with %10 worm castings twice a year, tree specific organic fertilizer with chicken or steer manure and beneficial bacteria with mycorrizae 3 times a year covered with pine chips once a year. I also purchased some earth juice micro blast just in case I see micro deficiency. And to help bring down the Ph of my soil I have been using an elemental sulfur blend combined with compost and OM. I figured my soil had been depleted so bad from my grandfather using nothing but chemicals over the last 40 years that I would bring the soil back to its natural best. So far things are looking good and more earthworms are returning. I had ZERO before so any is a plus:-)

To answer the OPs question...If your tree is small enough you can just squeeze the CLM (youll find it on one side of the leaf kind of wrapped in it) with your fingers and they will pop and die. No need for chemicals.

Here is a link that might be useful: {{gwi:594521}}