§ DEPARTMENT CIRCULAR 409, U. S. DEPT. OF AGRICULTURE 
In grouping these tests for Figure 5, account is taken only of the 
date of the first of the two applications. No showing is made of 
the treatments begun after May 5; these were too late to be highly 
effective. 
It is apparent that there is only slightly increased benefit from 
two applications as compared with one well-timed application, not 
enough to justify the doubled expense of the spray operation. It 
will be noted that two-spray operations starting before April 15 
gave better results 
than those started 
during the period 
for best single-spray 
control, April 15 to 
Mey 5. as 1 to 
e expected when 
---|- WW? APPLICATIONS STRING APOE ME: one considers that 
THO APPLICATIONS STHCTIWE BLIDRE ARSE In most cases the 
former plots re- 
ceived the second 
application some 
time during this 
period of best single- 
spray control and 
that their first ap- 
plication was during 
the second-best 
period. On the 
other hand, when 
spraying started 
during the period 
from April 15 to 
May 5, the second 
application fell, as 
a rule, during the 
oO . ‘ . 
OG 6 9 #21 6 ae wa a0 a3 36 ‘hird-best period for 
DAKE single-spray control. 
Fie. 5.—Development of all rots in oranges from plots re- Two-spray tests 
cons two app cations of 3—3—50 perecndy mie starting after May 5 
plus 1 per cent oil and from unsprayed plots during the 
36 days of the teste Each line shows Eayeighind aver. were not very nu- 
age percentages based on a tests made during six ha 
years, 1920-1925, for plots receiving the first of the two merous for the ee 
Spray applications within the seasonal period indicated son that this line of 
testing was discon- 
tinued after two years, when it was clear that spraying begun 
so late gave relatively slight control. A considerable number of 
late-season plots were sprayed three or more times without show- 
ing as good control as was obtained by a single earlier applica- 
tion. 
Three-spray tests during April and May gave better control than 
two-spray tests during the same period, but such a frequent schedule 
is not practicable. 
ALR. OCLNI 
