Florida Agricultural Experiment Station


on trees of any size from nursery trees to old bearing ones. It
rarely develops on trees that have been maintained in a vigorous
condition but is confined largely to trees that have become
weakened or injured as a result of inadequate fertilization, over-
cropping, drought, cold, injury from spraying, and attacks of
insects and other diseases, in which case the weakened twigs and
branches may be attacked and the unhealthy condition of the
trees becomes accentuated. In reality, withertip on citrus trees
other than limes, is largely a secondary trouble. The importance
of withertip and anthracnose have been so overemphasized in
past years that they still constitute a great bugaboo in the minds
of many Florida growers. With the exception of the form on
limes, which is distinct from that on other citrus trees, it is
obvious that these diseases cannot be regarded of as much im-
portance in Florida as they were formerly.
 In southern Florida and the West Indies, withertip and an-
 thracnose frequently cause serious damage to the buds, blossoms,
 young fruits, and shoots of the variety of lime variously known
 as the West Indian, Mexican, or Key lime. The only other lime
 or Citrus variety that has been observed to be attacked by this
 form of withertip and anthracnose is the Dominican Thornless
 lime, which supposedly originated as a sport from the West In-
 dies. The organism which causes withertip and anthracnose of
 the lime is somewhat different from that causing these diseases
 of other citrus fruits and is much more severe in its effect, fre-
 quently causing serious losses to growers of limes in southern
 Florida and parts of the West Indies.

 SYMPTOMS
 Since there are a number of different phases of this disease,
depending upon the part of the tree attacked, the symptoms
will be discussed under the following three subheadings, namely,
withertip, anthracnose, and russeting and tear-staining.
 Withertip:-The term "withertip" is applied to the withering
and dying back of twigs and branches attacked by the fungus
causing this disease. On the various kinds of citrus trees other
than limes, it is the mature twigs and branches that are attacked
by the withertip fungus. The dying back often progresses slow-
ly, with the leaves turning yellow, withering and dropping grad-
ually. However, in some cases, it may be sufficiently rapid to
cause the leaves to wither and dry up before the abscission layer