70 
PLANT QUARANTINE AND CONTROL ADMINISTRATION [April-June, 
Condition of plants. — Dilute carbon disulphide is least injurious to roots when 
the plants are dormant or semidormant, and treatment should be applied at 
that time. 
Dosage. — The dilution depends upon the temperature of the soil during the 48 
hours following application, and may be determined from Table 5. 
Table 5 
Minimum 
Miscible 
soil tem- 
carbon 
perature 6 
disulphide 
inches be- 
per 10 gal- 
low the 
lons of 
surface 
water 
°F. 
C.c. 
40-50 
97 
50-60 
81 
60-70 
65 
The concentration of the emulsion must not be greater than is necessary, as 
this may injure the plants. 
The dosages which must be applied under different conditions are given in 
Table 6 or 7. 
Table 6. — Dosage for circular collars 
Miscible carbon disul- 
Miscible carbon disul- 
Diam- 
eter of 
Water 
phide 
Diam- 
eter of 
Water 
phide 
collar 
40-50° 
50-60° 
60-70° 
collar 
40-50° 
50-60° 
60-70° 
F. 
F. 
F. 
F. 
F. 
F. 
Inches 
Gallons 
C.c. 
C.c. 
C.c. 
Inches 
Gallons 
C.c. 
C.c. 
C.c. 
12 
2.0 
19 
16 
13 
33 
15.0 
146 
122 
97 
15 
3.0 
29 
24 
20 
36 
17.5 
170 
142 
115 
18 
4.5 
44 
36 
29 
39 
21.0 
204 
172 
137 
21 
6.0 
58 
49 
39 
42 
24.0 
233 
195 
156 
24 
8.0 
78 
65 
52 
45 
27.5 
267 
233 
179 
27 
10.0 
97 
81 
65 
48 
31.5 
305 
255 
205 
30 
12.0 
116 
97 
78 
Table 7. — Dosage for square collars 
Miscible carbon disul- 
Miscible carbon disul- 
Length 
phide 
Length 
phide 
of side 
of 
Water 
of side 
of 
Water 
collar 
40-50° 
50-60° 
60-70° 
collar 
40-50° 
50-60° 
60-70° 
F. 
F - 
F. 
F. 
F. 
F. 
Inches 
Gallons 
C.c. 
C.c. 
C.c. 
Inches 
Gallons 
C.c. 
C.c. 
C.c. 
12 
2.5 
24 
20 
16 
33 
19.0 
184 
154 
124 
15 
4.0 
39 
32 
26 
36 
22.5 
218 
182 
146 
18 
5.5 
53 
44 
36 
39 
26.0 
252 
210 
168 
21 
7.5 
73 
62 
49 
42 
30.5 
296 
247 
198 
24 
10.0 
97 
81 
65 
45 
35.0 
340 
284 
228 
27 
12.5 
121 
101 
81 
48 
40.0 
388 
324 
260 
30 
15.5 
150 
126 
101 
Temperature of the soil. — Begin treating in the spring when the minimum 
soil temperature at a depth of 6 inches remains above 40° F. using 97 c. c. of 
miscible carbon disulphide to 10 gallons of water. When the minimum soil 
temperature at this depth remains above 50° P. decrease the concentration 
to 81 c. c. to 10 gallons. When the minimum soil temperature remains above 
60° F. decrease the concentration to G5 c. c. to 10 gallons. In the autumn, as 
the minimum temperature of the soil decreases, it is necessary to increase 
the concentration in the opposite order. Treatment must be discontinued 
when the minimum soil temperature at the 0-inch depth is below 40° F. 
