CITRUS MELANOSE AND ITS CONTROL 
45 
and that sulphur and weaker copper sprays are not satisfactory 
against this disease. There seems to be no commercial advantage in 
using more than one application of 3-3-50 Bordeaux plus oil emul- 
sion if this is properly timed. It is also evident that an application 
made several weeks in advance of the main outbreak is not as ef- 
fective as one put on just ahead of the principal infection period. 
Rainfall during the spring months of 1923. — The rainfall at Or- 
lando, Fla., during the spring months of 1923 is shown in Figure 10 
as an aid in interpreting the results obtained in the spraying experi- 
ments. Figure 10 shows that March was rainy, that April was not 
especially dry, and that the May rains set in on the 3d of that month. 
A slight amount of melanose showed up plainly on the new leaves 
and fruit in late March, but it was not until the rainy period of early 
Mav that severe infection occurred. After the middle of Mav the 
3.0 
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Fig. 10. — Rainfall (in inches) 
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it Orlando, Fla., during 
June, 1923 
March, 
April, May, 
and 
weather was especially conducive to infection, but by that time most 
of the fruit had grown too large and tough to become further in- 
fected. This resulted in a slight March infection on practically all 
fruit, but owing to the fact that -the fruit had become unusually large 
by the middle of May a noticeably small proportion was blemished 
very severely by this disease^ 
A grapefruit grove near .Leesburg in Lake County, Fla.. and an- 
other near Brownville in De Soto County were sprayed experimen- 
tally during February and March for scab control, and counts were 
also made for the effect of these early sprays on the prevention of 
melanose. The first application was made just as the spring leaf buds 
were swelling, the second toward the end of the blooming period, 
and the third, when applied, three weeks later. In general, melanose 
infection was about as severe on the plots receiving sulphur sprays 
as on the unsprayed plots, but the plots receiving one, two, and three 
applications of Bordeaux mixture during the early growing period 
were fairly well protected from the disease. From these experi- 
