citrus scab: its cause and control. 
29 
tions were made with a power outfit developing about 300 pounds 
pressure, and as a rule the sprays were applied with great thorough- 
ness. 
The following year the first applications were delayed until a 
reasonable amount of infection had taken place throughout the nurs- 
ery, and were made at intervals of 14 days. The same power outfit, 
pressure, etc., were employed, and the spraying was done as thor- 
oughly as could be expected under commercial conditions. Table 
10 shows the results of spraying experiments for the control of citrus 
scab in a sour-orange and rough-lemon nursery at Orlando, Fla., 
during 1919 and 1920. 
Table 10. — Scab control in the citrus nursery in 1919 and 1920. 
Formula. 
Year. 
Spray materials used. 
Spray injury on 
foliage or twigs. 
Control of scab. 
No. 1 
1919 
No. 2.. . 
1919 
Xo. 7 
Xo. 9. 
1919 
1919 
No. 10 
Xo. 1 
Xo. .' 
No. 3 
1919 
1920 
1920 
1920 
Xo. 4 
1920 
Xo. .-> 
1920 
No. 6 
No. 8 
Check 
1920 
1920 
1919 
Check 
1920 
Plain Bordeaux mixture, 3-3-50 : None 
Bordeaux mixture, 3-3-50, plus 0.5 per ! do 
cent oil as emulsion . 
Burgundy mixture Russeting of leaves 
moderate. 
Lime-sulphur solution Defoliation serious. 
.do 
Absolute. 
Do. 
Do. 
Lime-sulphur solution plus 0.5 per 
cent oil as emulsion. 
Plain Bordeaux mixture, 3-3-50 None 
Bordeaux mixture, 3-3-50, plus 0.5 per do 
cent oil as emulsion. 
Bordeaux mixture, 2-2-50, plus 0.5 per do 
cent oil as emulsion. 
Bordeaux mixture. 1-1-50, plus 0.5 per do 
cent oil emulsion . 
Commercial Bordeaux paste plus 0.5 do 
per cent oil as emulsion. 
Homemade Bordeaux paste do 
Copper soap do 
Moderate, about 
50 per cent. 
Do. 
Absolute. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Very severe in- 
fection, 90 per 
' cent. 
Serious infec- 
tion, somewhat 
less than 1919, 
72 per cent. 
At the end of each year 1,000 or more leaves were selected at 
random and counted for each plat and the presence or absence of 
citrus scab recorded. 
The beneficial results associated with citrus-scab control were 
very evident during the progress of the work. It was especially 
noticeable during the spring and early summer of 1919. On June 
30, 1919, measurements of growth in height were made over the 
various plats. At that time and throughout the rainy season of 
June and July the stunting effect of citrus scab was conspicuous. 
When the rains stopped and dry weather set in, thereby largely 
preventing citrus-scab infection, the check plat made a surprisingly 
rapid growth until checked by cold weather. 
