Florida Agricultural Experiment Station


southern ones. Since many fungous diseases and insects syn-
chronize with the trees in their growth activities, there may
also be a corresponding variation in the seasonal development
of the various pests that attack the new growth. Moreover, the
amount and time of occurrence of the rainfall varies greatly
from year to year; hence, no exact date can be set for spraying
in each year. In order for spraying to be effective, the grower
must observe the growth of the trees and weather conditions
and consider them carefully in relation to the development of
the diseases and insects that commonly affect the quality and
quantity of his fruit. Citrus fruit cannot be grown with profit,
or at least not with the maximum profit, by rule of thumb or
haphazard practices. The following spray schedule is recom-
mended for Florida citrus fruits:-

TABLE II.-SPRAY PROGRAM FOR PRINCIPAL FLORIDA CITRUS DISEASES AND
 INSECTS, ARRANGED BY SUBJECTS.
 By Arthur S. Rhoads and E. F. DeBusk, Pathologists,
 and J. R. Watson, Entomologist.

 SCAB


Time of Application


First application
 Just before growth
starts in the spring.


Second application
 In the last of the
bloom, when at least
two-thirds of the
blossoms have fallen.


 Materials Used


 3-3-50 bordeaux mix-
ture plus 6% quarts of
oil emulsion to 1 00
gallons
 or
 Lime-sulphur s o 1 u -
tion, 1 part to 25 or 30
parts of water.


 Remarks


 Important where condi-
tions favor heavy scab in-
fection, in which case it
should be followed by the
second application. Lime-
sulphur, although much less
effective than bordeaux-oil
emulsion, may be preferred
when it is desired to control
rust mites on late fruit.


 3-3-50 bordeaux mix- Important where condi-
ture plus 31/3 quarts tions favor heavy scab in-
of oil emulsion to 100 fiction, or where the pre-
gallons ceding application has not
 or been made. While the bor-
 Lime sulphur solu- deaux-oil emulsion is much
tion, 1 part to 40 parts more effective, lime-sulphur
of water. may be more desirable
 where control of red spi-
 ders, or of rust mites on
 late fruit is important. If
 I aphids or thrips are numer-
 Sous, add nicotine sulphate
 at the rate of 1 pint to each
 100 gallons of spray mix-
 ture (see note 4).