Cells between the oil glands are often not affected or only slightly collapsed. In contrast, oil spotting typically damages outer layers of cells, and the underlying oil glands often remain intact. Susceptible Varieties All types and varieties of citrus can suffer damage from oleocellosis, but those with numerous, prominent oil cells are particularly vulnerable. Oleocellosis occurs on all varieties of citrus, but in Florida it is most severe on Parson Brown and Navel oranges, grapefruit, Temples, tangerines, lemons, and limes. Turgid and Small Fruit Turgid fruit, particularly when harvested under foggy, wet, or humid conditions, are most likely to develop oil spotting.
Small sizes tend to be more susceptible to oil spotting than large sizes.
Time of Day Fruit turgidity is greatest, and hence the danger of oil spotting is most serious, early in the morning. It is particularly hazardous to pick susceptible crops when the dew is still on them. Even after visible dew on the fruit surface has evaporated, time must be allowed for turgor pressure to decrease. Evaporation time may be minutes in hot windy weather or hours on humid overcast days. The green color results from oil damage that prevents the conversion of chloroplasts to chromoplasts during degreening.