The smallish, well-loaded tree of Lemon Zest that I observed this year, had about 90% of the fruits destroyed by what appears to be Mango Bacterial Black Spot. Although one side of the fruits was usually edible, the bad side was too gross to present, not even on a "severely-defective-mangos-for-chutney" table. I hope we find some effective protocol for prevention of MBBS, as Lemon Zest is way too wonderful a fruit to give up on.
Po Pyu Kalay / Lemon Meringue was also very affected by the apparent MBBS, but less than 10% were destroyed, while more than half had several very small, very black, raised, split and oozing spots. This decreased in frequency when I switched to sanitation harvesting, picking fruits of all varieties as soon as the spots became obvious, as the chance is reduced to zilch that any increase in value will occur from leaving the fruits longer on the trees. So the fruits are blemished and often greener than we would like. Not having fruits with active oozing on the trees does give some fruits a chance to be clean.
I have not observed Orange Sherbet in the presence of this disease.