Bulletin 229, Diseases of Citrus in Florida


California. It starts as a light to drab-colored sunken area at
the base of the nipple or tip (Fig. 59) and progresses until from
about one-third to one-half the fruit is involved. In occasional
instances the trouble may start at the stem end or on one side
of the fruit. The affected portion of the rind has a watersoaked
appearance and is sunken somewhat below the level of the
healthy surface, but remains firm. The tendency of the fruit to
develop this decay on trees about the time it ripens constitutes
an undesirable feature of this otherwise highly desirable lime
variety.




















 Fig. 59.-Stylar end rot of Tahiti limes.

 The cause of this trouble is not known but it has been thought
to be a physiological breaking down of the rind since cultures,
made in the early stages of the trouble, consistently fail to yield
an organism. In the later stages of the trouble, however, Col-
letotrichum, Diplodia, Oospora, and other fungi have been found
associated with the disease in Florida. These fungi, which ap-
pear to be purely secondary, rapidly bring about the decay of
affected fruits after the trouble has started. Since stylar-end
rot occurs in greatest abundance as the fruit approaches ma-
turity, part of the loss can be avoided by picking the fruit before
it becomes too mature.