28 BULLETIN 1482, IT. S. DEPT. OF AGRICULTURE 
orchard suffered the heavy curculio infestation of 54.1 per cent for 
the harvested fruit and 64.8 per cent for the "drops." This is the heav- 
iest infestation of the curculio in any orchard of those in which were 
tested the spraying and dusting schedules considered in this publica- 
tion. The difference between the curculio infestations of the " drops" 
in the Hiley and Elberta orchards is in all probability due to the fact 
that because of a late spring the beetles did not begin to appear from 
hibernation in numbers until after the calyces of the Hiley peaches 
had begun to dry. This would cause them to seek the Elberta calyces 
for feeding purposes, as these remain green later than do those of the 
Hiley variety. The occurrence of first-generation adults in the 
orchards just before the harvest of Elberta peaches, in addition to 
the few adults surviving the preceding winter, caused the infestation 
of the Elberta peaches to be greater at harvest time than that of the 
other variety. The frequent rains also greatly promoted the devel- 
opment of brown rot and scab in the Elberta orchard, as indicated 
by a brown-rot infection of 30.3 per cent, and a scab infection of 89.7 
per cent, in the check plat. All of the treatments with spraying and 
dusting were therefore tested much more severely on the Elberta 
peaches than on the Hileys. The severity of the test to which the 
treatments were put can be realized by noting the proportion of 
sound fruit harvested from Plat V, which received no treatment at 
any time in the season. In Table 18 it may be seen that this, the 
check plat, produced only 2.9 per cent of sound fruit at harvest, the 
remaining 97.1 per cent being damaged by the curculio, brown rot, or 
scab. 
In interpreting the results of this work it must be kept clearly in 
mind that the efficiency of the early application of arsenate of lead 
must be judged largely from the table giving data on the infestation 
of the " drops," as the early arsenical treatment is applied especially 
for the control of the curculio in the " drops" and has a bearing on 
the control of the insect from the time of application until the fruit 
is harvested. The. efficiency of the late application of arsenate of 
lead can be measured only from tables giving results in harvested 
fruit, as practically all " drops" have fallen before this application is 
given. 
The value of the arsenate of lead spray applied just as soon as the 
petals are down, especially in years when the curculio infestation is 
heavy, is again clearly demonstrated by the results of the experi- 
ments on Elberta peaches. Table 19 shows that of the " drops" 
from Plat II, which did not receive the early arsenate of lead spray, 
13.0 per cent were infested with the curculio, whereas in the case of 
Plat I, which received the early treatment, only 6.2 per cent of the 
" drops" were infested. Again, the treatment of Plat I with arsenate 
of lead when 75 per cent of the petals had fallen reduced the curculio 
infestation of the " drops" a little over 50 per cent. A reduction 
of the infestation in the " drops" has a corresponding effect on the 
infestation in the harvested fruit, as revealed in Table 18. Of the 
fruit harvested from Plat II, which did not receive the early spray 
of arsenate of lead, 28.5 per cent was wormy, whereas there was an 
infestation of 21.9 per cent in the case of Plat I, which was treated 
with that spray. 
The curculio infestation of the " drops" from Plat III, which was 
dusted on each occasion for treatment, was 8.5 per cent (Table 19), 
