Florida Agricultural Experiment Station


on dead citrus bark. Phomopsis usually develops most abun-
dantly in the bark of small twigs and fruit stems that have died
recently, while Diplodia occurs most frequently in the bark of
larger twigs and limbs. The spores developed in the pustules
of these respective fungi on the dead bark are disseminated dur-
ing periods of warm, rainy weather.


Fig. 57.-Diplodia stem-end rot of orange illustrating the tendency of this
 decay to progress downward in streaks in advance of the main decay.

 While stem-end rot may begin while the fruit is still hanging
on the tree, it usually develops after the fruit has dropped or
after it has been picked. The length of time for stem-end rot
to develop in the fruit after picking varies considerably with the
temperature and length of time which it is held. The chief fac-
tor contributing to the development of stem-end rot in fruit is
the presence of dead wood in the trees. The rate of development