Florida Agricultural Experiment Station


of Diplodia stem-end rot 50 percent, it had comparatively little
effect on the amount of Phomopsis stem-end rot. The difference
between the degrees to which these stem-end rots can be con-
trolled by pruning appears to be due to the fact that Phomopsis
is found for the most part on the innumerable small dead twigs
and fruit stems that cannot be removed with the same degree
of thoroughness in commercial practice as can the larger dead
wood which produces the majority of the Diplodia spores.
 2. Spraying:-It has long been known that applications of
 bordeaux-oil emulsion, properly timed to control melanose, will
 also decrease the amount of Phomopsis stem-end rot, both of
 which are caused by the same fungus. In some storage tests that
 followed spraying experiments, conducted by Winston, Fulton,
 and Bowman for three successive years, it has been shown that
 one or two applications of bordeaux-oil emulsion, made between
 April 15 and May 5 for melanose control, reduced Phomopsis
 stem-end rot about one-half, but had only slight effect upon the
 control of Diplodia rot. To judge from these results, it is doubt-
 ful if the grower would be justified in spraying more than that
 required for melanose control in order to control stem-end rot.
 However, the control of stem-end rot may be regarded as an
 added inducement to undertake spraying for melanose control.
 3. Removal of Stem Buttons During the Coloring Process:-
 The experimental work of Rogers and Earle in Cuba, and of Win-
 ston, Fulton, and Bowman more recently in Florida, demon-
 strates that stem-end rot may be materially reduced by removing
 the stem buttons. The latter workers found that the "gassing"
 method adopted a few years ago in Florida for coloring citrus
 fruit loosened and removed most of the buttons without injuring
 the fruit. Their tests showed that, in addition to reducing the
 amount of stem-end rot, the removal of the buttons by "gassing"
 also reduced the amount of blue mold decay and that gassed
 fruits with the buttons left intact kept hardly as well as un-
 treated fruit. Fulton reports that the removal of the buttons
 within four or five days after the fruit has been picked prevents
 practically 90 percent of stem-end rot of both types.
 4. Antiseptic Treatment of the Fruit:-In tests with the borax
 treatment of citrus fruit for reducing blue mold decay, Fulton
 has found that the amount of stem-end rot normally developing
is also reduced by this treatment.