Under drier conditions the spots do not enlarge but turn reddish brown giving a speckled appearance.
Numerous spots cause infected leaf parts to yellow, wilt and die.
Under moist air conditions large mounds of bacterial ooze appear on the lower surface of the spots. Dried ooze is a waxy, silvery- white layer covering the spots. The ooze may later appear on the upper surface of the spots. Prevention includes avoidance of lower temperatures, crowding and syringing. A fungal leaf spot causes very small reddish brown lesions on the young leaves.