18 BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE [Jan.-Mar. 
(vi) The condition of the soil and the apparatus used and the method of appli 
cation of the fumigant must meet with the approval of an authorized inspector of 
the United States Department of Agriculture. 
(2) Methyl bromide f umigation. — (i) Potting soil must be treated in a container 
with methyl bromide in a dosage of 40 cubic centimeters of methyl bromide per 
cubic yard of soil for a period of 48 hours. 
(ii) The sides, bottom, and seams of 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. 
(iii) The temperature of the soil shall not be lower than 40° F. during the entire 
time of treatment. 
(iv) The condition of the soil and the apparatus used and the method of appli- 
cation of the fumigant must meet the approval of an authorized inspector of the 
United States Department of Agriculture. 
(3) Heat treatment. — (i) Live steam, under pressure of 80 pounds or more per 
square inch, shall be applied through a grid of perforated pipes at the bottom of 
the sterilizing box or truck body containing the soil, for a period of 45 minutes 
or until all parts of the load reach a temperature of 200° F. 
(ii) The grids shall be constructed of 1-inch pipes, perforated with holes 
A inch in diameter on the upper side and connecting at one end to a manifold into 
which the steam is introduced. 
( iii) The layer of soil in the sterilizing box shall not be more than 2 feet, 6 inches 
deep. 
(4) Methyl bromide and carbon disulphide. — (See instructions in para- 
graph (c).) 
(c) Soil plots, plunging beds, and pottmg soil. 
(1) Methyl bromide. — (i) Inject the liquid methyl bromide into the soil at a 
depth of 6 inches by means of a hollow needle or other suitable injector at the 
rate of 4.7 milliliters per square foot or 7 milliliters per 1% square feet of soil 
surface. 
(ii) After treatment has been applied to the plot the soil should be covered 
with 10- or 15-pound building paper, lapped 4 inches and weighted down so that it 
will not be blown off. 
(iii) The soil must be at a temperature not lower than 45° F. at a depth of 
6 inches when the treatment is applied. At temperatures from 45° to G2° inclusive 
the soil must be kept covered for a period of 6 days to insure complete mortality 
of all eggs, larvae, pupae, and adults of the insect which may be present in the soil 
under treatment. At temperatures above 62° the soil must be kept so covered for 
a period of not less than 4 days. 
(2) Carbon disulphide. — (i) The insecticide shall be applied at the rate of 
33 milliliters per square foot of soil surface, the liquid to be poured into holes 
at least 6 inches deep and 1 inch in diameter at the top, and covered immediately 
with earth. 
(ii) After application the plot should be covered with 10- to 15-pound building 
paper which shall remain in position for at least 4 days in order to insure complete 
mortality of any eggs, larvae, pupae, or adults of white-fringed beetles that may be 
present. 
(iii) The treatment shall not be applied to soil which is below 80° F. in 
temperature at a depth of 6 inches. v 
(d) Disclaimer. — There has been opportunity to test these treatments on only 
relatively few varieties of plants and in authorizing the movement of potted 
plants, nursery stock, or soil treated according to the requirements stated nbove, 
it is understood that no liability shall attach either to the United States 
Department of Agriculture or to any of its employees in the event of injury to 
cither plants or operators. 
(e) Caution. — (1) Methyl bromide. — (i) Methyl bromide is a gas at ordinary 
temperatures. It is colorless and practically odorless in concentrations used for 
fumigation of plants or potting soil. It is a poison and the operators should 
use gas masks approved by the United States Bureau of Mines for use with 
methyl bromide, when exposed to the gas in concentrations used in fumigation, 
or while preparing the solution. The plants in the fumigation chamber should 
be well aerated by blowing air through them, and the room adequately ventilated 
before it is entered. After fumigating the potting soil by methyl bromide the 
cover should be removed and the soil allowed to become aerated. 
Cii) The method for application of methyl bromide described in paragraph 
(c) provides a closed system in which the operator is not exposed to a dangerous 
concentration of the gas provided there is no leakage in any exposed portion of 
