Bulletin 229, Diseases of Citrus in Florida


that this disease was a serious menace to the citrus industry and
its true cause vas not demonstrated until 1915.
 Canker attacks all kinds of citrus trees of commercial impor-
tance in Florida, provided the conditions are favorable for the


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 Fig. 11.-Canker on grapefruit leaves and twig.
development of the disease. The grapefruit is attacked the most
severely, however, and for this reason citrus canker threatened
to cause far more serious damage here than in the other Gulf
States, where the Satsuma orange, a much more resistant spe-
cies, is of greatest commercial importance. The trifoliate orange
is probably next in susceptibility, followed by the limes other
than Tahiti, sweet oranges, American-grown lemon varieties,
and the Satsuma orange. Mandarin oranges, calamondins and
citrons have a very slight degree of susceptibility and are com-
mercially resistant. The kumquat is highly resistant. Inocu-