Florida Agricultural Experiment Station


pact, bushy head (Fig. 66). Withertip is often associated with
exanthema, the weakened condition of the trees caused by the
latter disease affording an excellent opportunity for the develop-
ment of the former one.
 On the Leaves:-The younger trees that have developed ex-
anthema, or that may be on the verge of developing this trouble,
commonly exhibit an exceptionally deep green color of the foli-
age. The leaves are often very large and coarse and show symp-























Fig. 64.-Exanthema on orange twigs, showing bark excrescences. The
 twig at the left shows most staining. (Natural size.)
toms of over-vigorous growth. The same characteristic resin-
ous, reddish-brown staining may occur on the leaves as occurs
on the twigs, in which case it appears principally on the stalk,
base, and lower part of the midrib. In rare instances, the same
type of small corky eruptions commonly occurring on the twigs
and fruit may develop at intervals along the midribs and at other
points on the leaves, especially on the under surfaces. The same,
or closely related, conditions which induce the development of
exanthema often lead to the development of mottle-leaf, so that
the latter disease may sometimes be associated with the oc-
currence of the former one.