Bulletin 229, Diseases of Citrus in Florida


 CONTROL OF MELANOSE
 As early as 1896, Swingle and Webber showed that melanose
outbreaks could be greatly reduced by applications of copper
sprays. However, in spite of the fact that these investigators
had demonstrated this point, few, if any, growers attempted


 Fig. 7.-Melanose on grapefruit, showing mud-cake type.
to control melanose by spraying because the injurious effects
resulting in a great increase in scale-insects following applica-
tions of copper sprays were usually more damaging to the trees
and fruit than the melanose.
 The control of melanose was considered impractical by the
growers until 1912, when Stevens found that the disease was
caused by a fungus (Phomopsis citri) that produces its spores
on dead twigs and branches. Following this, it became the gen-
eral practice to prune for melanose control. However, it later
became evident that thorough pruning to eliminate the dead and


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