Florida Agricultural Experiment Station


 The disease often may remain inactive for a considerable per-
 iod of time after infections have taken place before developing
 the usual symptoms and evidently can be carried over long per-
 iods in lesions on older bark. Lee, Fulton, and Loucks have each
 shown that the canker organism in grove soils cannot compete
 with the soil organisms occurring in such soils. From these and
 other investigations that have been made in regard to the longev-
 ity of the citrus canker organism in soils, it appears that most
 agricultural soils cannot long retain the possibility of dissem-
 inating it.
 CONTROL OF CANKER
 The prompt and complete destruction of all canker-infected
trees is the only safe and practical method that has yet been
found for checking the disease in Florida. This can be done to
best advantage by burning them in place with blasts of flame
from the nozzle of a small spraying outfit filled with kerosene
or other suitable fuel oil. Any citrus canker, or suspected cases
of this disease, should be reported promptly to the State Plant
Board at Gainesville, who will attend to the eradication of the
disease.
 FOOT ROT
 Caused by Phytophthora parasitica Dastur
 Foot rot, collar rot, or mal di gomma to use the well-known
Italian name, is a gum disease which is probably more wide-
spread than any other citrus malady, being known to occur in
virtually all countries where citrus trees are cultivated. This
disease seems to have been noted in Florida first about 1876,
although it evidently did not become an important disease in
this state until after 1880. While foot rot has been a destructive
disease in Florida citrus groves for many years, it does not ap-
pear to be as severe as in some foreign countries and, as a rule,
does not attack the trees until they are quite old and have been
bearing fruit for several years. This disease is at present wide-
ly distributed throughout the citrus sections of the state and still
causes considerable loss in certain sections. In some cases the
majority of the trees in moderately old sweet seedling orange
groves may develop foot rot more or less simultaneously and
groves that were highly productive for several years may die
out within a short time. Foot rot, however, is by no means so