1942] 
SERVICE AND REGULATORY ANNOUNCEMENTS 
17 
circulated by means of a fan or blower throughout the entire 4-hour fumigation 
period. 
(v) The use of a fumigation chamber, lined with sheet metal throughout and 
with a metal-covered door closing against gaskets and held tightly in place by 
refrigerator door fasteners, is recommended. 
(2) Methyl bromide fumigation under partial vacuum. — (i) Fumigation under 
partial vacuum equivalent to at least 24.5 inches of mercury must be done with 
a dosage of 4 pounds of methyl bromide per 1,000 cubic feet of chamber space, 
including the space occupied by the commodity, with an exposure of iy 2 hours, 
the vacuum to be maintained throughout the entire period. 
(ii) The temperature of the soil balls shall be 75° P. or above, and the diam- 
eter of the soil balls shall be not greater than 11 inches if spherical, or thicker 
than 11 inches if not spherical. 
(iii) The fumigant-air mixture shall be circulated in the fumigation chamber 
by means of a fan the first 15 minutes of the exposure period to mix the vapor- 
ized fumigant thoroughly with the air in the chamber and bring it in contact 
with the surface of the soil balls. The soil balls shall be washed with one or 
more changes of air at the end of the exposure period. 
(iv) A standard vacuum fumigation chamber which can be closed tight and 
will withstand an external pressure of at least one atmosphere is required. A 
vacuum pump of sufficient capacity to reduce the pressure within the vacuum 
chamber to the equivalent of 3 inches of mercury (a 27-inch vacuum at sea level) 
in not more than 20 minutes is necessary. 
(3) Methyl bromide solution. — (i) Treatment method. — (Applicable to all 
regulated areas.) 
{a) The soil balls around the roots of plants must be buried in sand and 
plunged in boxes or trays which are watertight and approximately 1 foot deep. 
(6) A 2-inch space filled with sand shall be provided between the soil balls, 
also above and beneath them. 
(c) Such soil balls shall be treated with a solution of methyl bromide and 
alcohol at a concentration of 0.3 percent methyl bromide and 0.6 percent dena- 
tured ethyl alcohol by volume in water. The solution is to be prepared by first 
mixing the methyl bromide and alcohol together and then adding this mixture 
to the water and mixing thoroughly. 
(d) The aqueous solution of methyl bromide and alcohol shall then be applied 
evenly over the surface of the sand around the plants at the rate of 40 gallons 
per 100 square feet of surface area by means of a sprinkling can or sprayer. 
(ii) Type of material, exposure, and temperature. 
(a) In Orleans Parish, including the city of New Orleans, Saint Bernard Parish, 
and regulated parts of Jefferson and Plaquemines Parishes, La., the treatment shall 
be applied only to plants in soil balls not greater than 7 inches in diameter, nor 
greater than 7 inches in thickness when not spherical. After the required dosage 
has been applied, the soil balls shall remain embedded in the sand for a period 
of 8 hours. The temperature of the soil balls during the treatment shall not be 
lower than 65° F. 
I (6) In all regulated areas other than Orleans Parish, including the city of New 
Orleans, Saint Bernard Parish, and regulated parts of Jefferson and Plaquemines 
Parishes, La., the treatment shall be applied to soil balls not greater than 8 inches 
in diameter, nor greater than 8 inches in thickness when not spherical. After the 
required dosage has been applied, the soil balls shall remain embedded in the 
sand for a period of 6 hours. The temperature of the soil balls during the treat- 
ment shall not be lower than 62° F. 
(b) Potting soil. 
(1) Carbon disulphide fumigation. — (i) Potting soil shall be treated in a con- 
tainer with carbon disulphide at a dosage of 2 pounds per cubic yard of soil for 
a period of 48 hours. 
(ii) The grade of carbon disulphide shall be comparable to U. S. P. grade having 
a specific gravity of 1.25 at G8° F. 
(iii) The container shall be tight, preferably lined with sheet metal, and shall 
have a tight cover or be covered with a tarpaulin immediately after the fumigant 
is applied. The container shall not be more than 36 inches deep. 
(iv) The soil shall be friable, and wet soil shall not be treated by this method. 
The fumigant shall be applied to the soil in holes 3 inches deep, the dosage to 
be evenly divided among holes 1 foot apart over the surface of the soil, and the 
fumigant shall be covered with soil as soon as it is applied. 
(v) The temperature of the soil shall not be lower than 40° F. during the entire 
time of treatment. 
