SPRAYING FLORIDA CITRUS FRUITS 11 
rot in the lots of fruit sprayed with lime-sulphur solution were about 
50 per cent greater than in the unsprayed fruit. | 
In 1921, tests were made with 1 and 2 applications of 1-40 lime- 
sulphur solution and with 1, 2, and 3 applications of dry lime- 
sulphur made up at the rate of 4.4 pounds to 40 gallons of water. 
All 5 of these tests gave more rot in the sprayed fruit than in the 
unsprayed checks. ‘This excess of rot in the sprayed fruit ranged 
from 17 to 36 per cent, and there was excess for Phomopsis as well 
as for Diplodia rot, relatively greater for the latter. 
TABLE 2.—Results of spraying experiments with 1-40 lime-sulphur solution and 
with 3-3-50 Bordeaux mixture plus 1 per cent oil for control of rot in 
oranges 
Percentage of effectiveness 
i for 36-day period 
Num- | Total 
Spray an¢@ applications ber of SS 
leeaaginen bite Phomop- | Diplodia 
| All rots |" sis rot 1 | rot 1 
EE 
140 lime-sulphur, 3 applications___-_- “Sees ee SS 4 | 5 | ll 33 2 —51 
3-3-50 Bordeaux plus 1 per cent oil, 2 or 3 applications--_| 4 | 7a 55 72 24 
3-3-50 Bordeaux plus 1 per cent oil, 1 application __--_--- 4 | 8 | 48 60 | 19 
ipreyed oo ee ee ees 4 0 | 0 0 0 
} | 
1 The percentages of effectiveness for Phomopsis and Diplodia considered separately are computed as 
follows: The 3-day rot caused by each fungus is divided by the number of fruits in the test during the par- 
ticular 3-day period; these percentages are added cumulatively; an average of values of such cumulative 
index figures is obtained by dividing by the total number of 3-day periods covered in the test; such average 
for sprayed fruit is subtracted from a similar average for the unsprayed check, and the difference is 
divided by the average for the unsprayed check to determine the percentage of effectiveness. 
? A minus value for the percentage of effectiveness means that the treated fruit developed more rot than 
the untreated checks. 
Similar excess in rot occurred during 1925 in the case of two 
tests of 2 applications of 80-20 lime-copper sulphate dust. In this 
case the Diplodia rot was almost 75 per cent greater in the dusted 
fruit than in the untreated, the Phomopsis rot was about the same 
as in the untreated, and the resultant, including all rots, was about 
10 per cent in excess of the total rot for the untreated fruit. 
No explanation can now be offered for this peculiar effect of the 
hme-sulphur preparations and of the lime-copper sulphate dust in 
agape favoring the development of the Diplodia type of stem- 
end rot. 
PROLONGATION OF KEEPING PERIOD 
From Figure 2 it is apparent that the oranges sprayed from 
April 15 to May 5 required about 2 days longer to develop 10 per 
cent of rot than did the unsprayed fruit, about 4 days longer to 
develop 20 per cent of rot, about 514 days longer to develop 30 
per cent of rot, and about 8 days longer to develop 40 per cent of rot. 
The unsprayed fruit showed these indicated percentages of rot in 
15, 19, 22, and 2514 days, respectively, being increases of 13, 21, 25, 
and 31 per cent, respectively, over the time elapsing before these 
several proportions of rot developed in the sprayed fruit. 
Probably nine-tenths of the Florida citrus fruit reaches destina- 
tion within 2 weeks from the time it is picked, the major portion of 
it between 1 and 2 weeks after picking. A period of 3 weeks 
from the tree ought to cover actual consumption of most of this fruit. 
