Bulletin 229, Diseases of Citrus in Florida


fog. The spores of the causal fungus developed in the pustules
are imbedded in a gelatinous matrix, which swells when moist-
ened. The spores are then forced out of the microscopic mouths
of the pustules in minute, tendril-like masses, after which rains


 Fig. 5.-Melanose on grapefruit.
or the drip of water from dew or fog wash them down over the
young leaves, twigs, and fruits, thereby leading to the infection
of these susceptible parts. Given frequent rains or heavy dews
or fogs, trees with dead wood of relatively recent origin may
thus continue to infect the growing tissues as long as they re-
main susceptible.
 It has been found that citrus foliage and shoots are very sus-
ceptible to infection from the time they emerge from the bud
until they harden distinctly, which usually takes place before
the leaves take on a deep green color. This means that, or-