please take a look at the underneath of the leaves. In the first picture, the leaves that look whitish and slightly speckled, appear like the symptoms of a really bad spider mite infection. If the underneath of the leaves are covered in tiny speckles (you can shake the leaf over a white pieces of paper, that will fall onto it, and they move), then that's the cause.

andrew, do you ever fertilize the tree? Your tree is very deficient in iron, and probably many other nutrients. The symptom off an iron deficiency is:.....NEW leaves with green veins on otherwise yellow leaf. An iron deficiency can be cause by the lack of the element iron, and also the deficiency is often caused by high pH rather than the shortage of the mineral.

I wonder if the pictures are bad quality as I don't see yellow. I only really see bright green, dark green, brown, and white (on the dead leaves).

I tried shaking the leaves onto a piece of paper and unless spider mites can fly I think the only pests that dropped onto the paper were whiteflies.I took some additional photos of the front and back of the leaves.

I fertilize my citrus trees every 2 weeks but I've never fertilized the tree in the pictures. I've always avoided it because they already grow so fast that they take constant trimming. What fertilizer would you suggest Silica?

The flies have spread to all of my trees with the exception of my Italian Cypress, but even the Italian Cypress looks to be suffering this year.

I've been applying Neem oil and have fertilized the tress but the issue is getting worse. The whiteflies have gone but the disease is spreading to all trees. please see my latest photo

You could be burning your plants with the spray.

You might talk to your local Extension Agency if there's something particular to your area. I'd hate to see you lose all of your trees.

Treat it with a fungicide.

Steven

first try to find out what type of fungus so u can treat the right type of fungus and check for plant viruses