Many trees are infected by many different disease and most of the time those disease really do no harm, they are simply there. For example the Acers (Maples) get Black Tar Spot and even in years when it is very noticeable it is not going to kill the trees, at least it has not in the hundreds of years that species has been infected with it. While it is a good idea to know what diseases affect many trees it is not always necessary to "do something" about them, except maybe make the soil the tree grows in into a good, healthy soil so the tree can grow strong and heatlhy and be better able to handle that disease.

Sometimes it will happen earlier in the year and the leaves will fall off and then put new leaves on. This late in the year it is completely normal. If it happens earlier in the year the plants will look ragged but not much you can do about it. As long as they get good moisture they are pretty maintenance free.

The leaf surface with the lightest variegation is indeed more susceptible to sunburn. The pigment chlorophyll functions as though it's nature's sunscreen for plants, and the lighter parts of the leaf have much less chlorophyll, so there's more potential for burn. I'd considered sunburn as a potential cause, but discounted it for a couple of reasons. Rachel said her plant was in a state of quiescence and had just started to grow new leaves. She also didn't indicate it was moved into a considerably brighter spot. Any leaves that existed on the plant prior to any new foliage would have already been conditioned to where the plant is sited; and, any new leaves that come into existence would be perfectly adapted to the photo load wherever the plant is sited. Too, many symptoms related to other issues tend to show up in the lighter parts of variegation, notably, over-watering, a high level of dissolved solids in the soil solution, and toxicities of one or more elements/compounds, particularly fluoride which I don't suspect to be the issue here. Given the info Rachel provided, I'd bet the plant was struggling because of too much water/not enough air in the soil, which limits the plants ability to take up and move water efficiently. Increasing the EC/TDS level of the soil solution by adding fertilizer salts further decreases the ability of the plant to make efficient use of water in the soil, which yields a plant potentially dying of thirst in a sea of plenty ...... at least until the issues are fixed. As an aside, I have a variegated F benjamina forest (a bonsai group planting with more than around 9 trees is referred to as a forest planting - fewer trees are a grove or clump planting) with 15-20 trees in it. It sits on a nursery cart on a cement slab in full sun from dawn until around 7PM and there is no sign of sunburn on any of the leaves ...... but that's not to say the leaves can't burn. They can and the lighter areas will prove more sensitive, just as you suggested. Al

this is a very large fast growing tree.. and it probably shouldnt be closer than 30 to 40 feet from the hosue ... minor leaf damage is irellevant.. imo ... the leaf is still functioning 99.9% ... there is nothing to do about it at this time... i would write it off as shipping.. from grower.. to seller.. to you .. and or transplant stresses .. ignore it ... i dont know what the pot pic is.. but you could do better with media for a tree ... and that tiny a tree .. might better off in a smaller pot.. even if you just stick the smaller in the larger ... [unless that it when you started it a few years back.. and you prevailed.. then 2 thumbs up] most trees want a sip of water.. then near total drainage.. your media has too much peat.. and could stay too wet.. unless you just dont water it all that often.. and let it near dry ... ken ps: my two foot whip stick planted 15 years ago.. is now at least 35 feet tall.. and 20wide .. basically thru the windows on the second level.. in the building in the pic... lol ..