Florida Agricultural Experiment Station


 Fruits blemished as a result of exanthema are commonly said
by growers to be "ammoniated". This term originated from the
supposed relation of the occurrence of this diseased condition
to the use of high percentages of ammoniatess", or nitrogenous
compounds, as fertilizers. However, the term is a misnomer,
for it gives rise to the erroneous impression that the trouble is
solely due to the excessive use of nitrogen.* It is much better to
speak of such fruit as exanthema-marked fruit.
 T wo general
 types of exanthe-
 1ma occur, namely
 the chronic and
 t h e temporary.
 The chronic type
 occurs where the
 disease has been
 brought o n by
 some improper
 soil or other con-
 dition of persist.-
 ent nature. In
 such cases, all of
 t the symptoms
 that have been
 described m a y
 occur in greater
 or less abundance
 ... and, if the causal
 .. condition or con-
 ditions continue,
 Fig. 66.-Orange tree severely affected by exan- the trees will be
 them. seriously injured
and may die. In the temporary type the disease usually does
not attain complete development and some one or more of the
symptoms may predominate while the others may be scarce or
even entirely absent. It frequently happens that the fruit is the
only part of the tree affected and that even the marking of the
fruit may not be accompanied by any extensive splitting or

 *In conformity with the usage recently adopted by the National Fer-
tilizer Association, the term "nitrogen" is used instead of the term "am-
monia".