I have three recently-planted citrus trees (Meyer lemon, Tangelo, and Mexican lime). All three plants are under three years old and potted prior to planting. Since I have planted them the set fruit dropped and now the leaves are beginning to yellow with spots. It began with the tangelo and has now spread to the others. I live in San Diego, CA. What is the disease/pest and is there a treatment? Thanks.
San Diego County California
The overall issue may simply be transplant shock, which the plants may outgrow over time if they are given the right fertility, planting depth, and irrigation. The large white area looks like sunburn, which may happen when plants are moved, pruned, or have leaf drop, which exposes previously-shaded leaves to full sun. It is made worse by drought or drying wind. The small insects look like they might be brown citrus aphid. A hard stream of water will remove them, but this will need to be repeated regularly. Take care in the application of any pesticides if the plants are in full sun, because there may be some burn if there are oils or soaps in the spray.