22 BULLETIN 1482, U. S. DEPT. OF AGRICULTURE 
The two sprays of sulphur, hydrated lime, and calcium casemate 
in combination with arsenate of lead, when used on Plats V and IX, 
gave essentially the same results as their application to the Hiley 
variety. Good control of both brown rot and scab resulted, but the 
bm-ning of the foliage was too severe to warrant an unqualified 
recommendation for its use. The sprays controlled curculio, brown 
rot, and scab in the experimental orchard of Elberta peaches better 
than did the dust. Plat VI (Table 11) had a curculio infestation of 
16.2 per cent, a brown-rot infection of 3.4 per cent, and a scab infec- 
tion of 24.5 per cent of the dust schedule, as against corresponding 
percentages of 6.1, 1.0, and S.6 for Plat I, sprayed with arsenate of 
lead. 
The dust containing SO per cent of sulphur, used on Plat VI, gave 
much better results than the dust containing 50 per cent, used on 
Plat VII. There was a brown-rot infection of 3.4 per cent, and a scab 
infection of 24.5 per cent in Plat VI: Plat VII had corresponding 
percentages of 7.3 and 44.1. 
Table 13 shows that the schedule used on Plat I. which was the one 
recommended to the growers for the season of 1923, resulted in the 
highest yield of merchantable fruit. 
EXPERIMENTS IN 1924 
Life-history studies of the curculio have shown that when the 
adults leave their hibernation late in the spring, and that when, also, 
the pupation season of the first generation is unusually cool and 
damp, only one generation occurs annually in Georgia. Spray 
schedules were therefore included in the program of experiments for 
1924, arranged to determine the best method of controlling the cur- 
culio when the first application of arsenate of lead is omitted. Such a 
schedule was checked against the regular schedule involving four 
treatments, carried out on an adjoining plat. Before the experiments 
were begun, colloidal sulphur, recommended for the control of brown- 
rot and scab, had made its appearance on the market. Tests were 
therefore included to determine the effectiveness and safety of this 
fungicide, with and without lime. Manufacturers had advised 
growers to use it without lime. The comparative effectiveness of 
the recommended dusting and spraying schedules was again tested. 
To determine the results obtained by keeping the fruit continuously 
covered with dust imtil the stage when the peach stone hardens, a 
plat was included which received after each rain an application of 
dust in the proportion of 0-5-95, from the falling of the petals until 
two weeks after the shedding of the calyces; an application of the 
80-5-15 dust was then given. The treatment for this plat was 
concluded with an application four weeks before harvest of spray of 
arsenate of lead and self-boiled lime-sulphur. A plat was also 
included at the beginning of the season to test the effectiveness of 
a 2 per cent nicotine dust against the curculio. This test was aban- 
doned after the second application had been made, as the results, 
correlated with the the results of feeding tests with nicotine dust in 
the insectary, had shown that the material was not sufficiently 
economical and effective to warrant further experimentation. 
Table 14 gives in outline the schedules tested in the spraying and 
dusting experiments in 1924. 
