Neem Oil is a surfactant that is also between 5% and 10% nitrogen (which might be why you have leaf burn). It can be used as a pesticide to smother baby spider mites and other weak organisms, but is better when combined with a real insect toxin -- such as organic pyrethrin. An example is given in the link below.

Here is a link that might be useful: Scotts Green Light Fruit Tree Spray

That's similar to a Bonide product I use; "Boneem". Both great products.
I really like the combo of pyrethrins and neem oil. A one-two punch that works better than either used separately. Really good on aphids, scale, mites, and whitefly.

For Citrus Leaf Miner, I prefer Systemic Imidacloped when the tree isn't bearing fruit and/or when it's young. When it's fruit bearing, Spinosad, and organic surface spray, works very well for CLM.

I also prefer Semitic insecticides while a tree is young. Easier on the foliage, having to treat less often is easier on the owner, and it does a better job on fast generation breeding insects.

As far as systemics it getting into the fruit, well, I don't think one should be growing fruit on a 1 to 3 year old tree. I would take it all off.

It's better to let it put it's energy into growing more canopy and roots, without the set back of insect infestations.

By the 4th year, you can do without the systemic insecticide and use the sprays as needed. The pyrethrin/neem oil combo great for aphids, scale, mites, and whitefly and is a surface spray and can be easily washed off fruit. For CLM, Spinosad.

BarbJP, we're of the same mind.

Folks new to Citrus and like-size fruit trees need to understand that every fruit you bring to maturity could have been a 3-4 foot branch. It's ridiculous to have fruit on immature trees. Ok, let the plant have sex and then remove the fruit sets -- perhaps leaving one on a spur from a large branch or trunk.

If you have an applicators license then Radiant SC is an upgrade to Spinosad, Baythroid XL is an upgrade to pyrethrin, Assail 30SG is a more environmentally (and bee) friendly nicotinoid, and Evergreen EC is a synergistic combination of pyrethrin, piperynol butoxide (distilled from sassafras), and aloe for surfactant.

Rotation and regular application is the key. Hitting the same insects with the same pesticide all the time is a recipe for disaster. In my location there is intense citrus leaf miner pressure and I spray or fertigate monthly to keep it down to a tolerable level. I also have a nursery stock license and live in a ACP quarantine zone so those folks come around every 90 days to make sure I'm meeting those requirements. To taunt them, I have a moderate size Curry Leaf Tree (the primary ACP host plant) which has zero pest problems.