CONTROL OF PEACH DISEASES IN GEOEGIA 
21 
Table 13. — Commercial results of fruit from all trees in each plat of the Elberta 
variety, peach spraying and dusting experiments, Fort Valley, Ga., 1923 
Plat 
Number of 
trees in 
plat 
Average 
merchanta- 
blefruit per 
tree (ex- 
pressed in 
cups; six 
cups equal 
one crate) 
Average 
cull fruit 
per tree 
(expressed 
in cups; 
six cups 
equal one 
crate) 
1 
148 
146 
158 
148 
77 
145 
155 
54 
79 
7.65 
7.15 
5.9 
4.95 
5.6 
4.05 
7.9 
3.8 
4.6 
0.7 
.7 
.6 
.6 
.6 
.5 
1.5 
1.75 
. 5 
II- 
III 
IV. 
V 
VI— 
VIIi 
VIII 2... 
IX 
1 Fruit damaged from curculio not graded out on this plat. 
2 In two portions, at opposite ends of the orchard. 
The spraying and dusting treatments for controlling the curculio 
received a much more severe test in the plats of Elberta peaches than 
in those of the Hiley variety during the season of 1923. Of the fruit 
harvested from the check (or untreated) plat, 28.2 per cent was 
infested with curculio larvse. Scab was more prevalent than is usual 
in central Georgia, the check plat having an infection of 67 per cent. 
Brown rot was not so serious; 11.9 per cent of the fruit in the check 
plat was affected with it. 
Owing to the fact that there was but one brood of the curculio in 
1923, the value of the early application of arsenate of lead was not so 
distinctly shown in the curculio infestation of the fruit harvested 
from the various plats. The early spray did, however, reduce the 
early infestation by the curculio, as evidenced by examination of the 
" drops." This reduction would have had a corresponding effect on 
the reduction of the infestation in the harvested fruit had there been 
two generations of the curculio. The " drops" from plats IV and V, 
neither of which received the early application of arsenate of lead, 
were more heavily infested by curculio than the " drops" from Plats 
I, II, and III, to all of which the early application was made 
(Table 12). 
The fruit harvested from Plat III, which received four applications 
of spray containing three-fourths of a pound of arsenate of lead to 50 
gallons of water, had an infestation of 8.1 per cent; the infestation of 
Plat I, which received three applications of spray containing 1 pound 
of arsenate of lead to 50 gallons of water, was 6.1 per cent. Because 
of the injury inflicted on the foliage sprayed, the schedule for Plat 
III is not so safe as the schedule by which Plat I was treated. 
Three applications of self-boiled lime-sulphur to Plat III gave no 
better control of brown rot (see Table 11) than did two applications 
to Plat I, and the control of scab was practically the same in both 
cases. The addition of calcium caseinate seemed to cause a slight 
increase in the effectiveness of the arsenate of lead against the curculio 
in Plat II, but it did not increase the effectiveness of the fungicide 
against brown rot or scab. 
