46 
BULLETIN 1474, U. S. DEPARTMENT OF AGRICULTURE 
mental data, together with the results obtained in former years on 
plots sprayed for citrus scab control, as well as in commercial groves 
in 1923, it is evident that melanose can be reduced decidedly by ap- 
plications of Bordeaux mixture during the scab-spraying season. 
But, generally speaking, much better results are obtainedlf the appli- 
cation is delayed until the latter part of April or the first of May, 
provided the weather during April is not extremely wet. 
SPRAYING EXPERIMENTS IN" 1924 
In 1924 spraying experiments were again conducted at Orlando in 
a mixed grapefruit and seedling-orange grove in which 31 sets of 
duplicated plots were sprayed with copper or sulphur sprays, but 
for the most part Bordeaux-oil emulsion was used. Spraying oper- 
ations were begun March IT, before many blooms had opened, and 
they were discontinued after June 28. Plots received from one to 
three applications at different times, as is shown in Table 11. 
Table 11. — Results of spraying experiments for melanose control with various 
materials on orange and grapefruit trees at Orlando, Fla., in 1924 
Materials used 
Num- 
ber of 
applica- 
tions 
Proportions 
Date applied 
Melanose infection 
Bordeaux oil emulsion.. 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
• Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Do 
Colloidal sulphur 
Lime-sulphur solution.. 
Lime-sulphur sludge 
Neutral copper acetate . 
Do 
Bordeaux-oil emulsion.. 
Bordeaux mixture 
Average of 13 check plots 
having no treatment. 
3-3-50+3/; 
oil. 
do... 
do... 
do... 
per cent 
3-3-50+1 
oil. 
do... 
do.._ 
do... 
per cent 
.ao. 
3-3-50+lH per cent 
oil. 
do 
3-3-50+H and 1 per 
cent oil. 
do 
do 
do. 
3-3-50+H, 1, and 1 
percent oil 
do 
3-3-50+2/2 and 1 per 
cent oil. 
2 do 
2 : do 
3-3-50+1 
on. 
do:.. 
do... 
do— 
5-50 
1-40 
do— 
per cent 
1-50 
do 
6-6-50+1 per cent 
oil. 
3-3-50 
Mar. 17. 
Mar. 27. 
Apr. 7... 
Apr. 17. 
Apr. 26. 
May 7.. 
May 16. 
May26. 
June 6.. 
June 16. 
June28 
Apr. 3, May 23. 
Apr. 3, May 1 
Apr. 7, May 24 
Apr. 7, Mav 1 
Apr. 8, May 1, 22.. 
Apr. 17, 30, May 10. 
Apr. 21, 28 
Apr. 21, Mav 10. 
Apr. 21, Mav 20. 
Apr. 26, May 10. 
Apr. 28, May 20. 
Apr. 25, May 26. 
May 7, 21 
Apr. 24, May 17_ 
Apr. 23, May 17. 
Apr. 24, May 16, 
Apr. 23, May 19. 
Apr. 23.... 
Apr. 22... 
Apr. 19. 
Per 
cent 
19 
35 
63 
Per Perl Per 
eni 
13 
32 
cent 
29 
31 
25 
19 
10 
17 
7 
11 
5 
15 
11 
17 
6 
19 
9 
23 
14 
20 
32 
17 
30 
21 
11 
12 
6 
14 
7 
16 
7 
6 
5 
12 
3 
13 
4 
13 
6 
13 
/ 
16 
6 
11 
5 
13 
4 
14 
7 
30 
27 
36 
25 
33 
28 
35 
29 
31 
33 
16 
10 
22 
25 
13 
24 
Per 
cent 
2 








2 
4 














2 





8 
