76 BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE [July-Sept. 
486, 489, and 503, are brought together in the present revision of this circular. 
In addition, the instructions as to treatment of balled nursery stock by methyl 
bromide solution as specified in paragraph (ii) of subsection (b) are somewhat 
modified as to treatments within the regulated areas other than New Orleans 
and vicinity. All treatments apply to both species of white-fringed beetles, 
Pantomorus leucoloma Boh. and P. peregrinus Buch., and are uniformly appli- 
cable to all regulated areas except the methyl bromide solution treatment of 
balled nursery stock, the specifications of which vary for the New Orleans 
area because of the type of soil in that locality. This circular supersedes all 
instructions in Circulars B. E. P. Q. 486 and 489, and previous issue of 503. 
§ 301.72-5c 2 Administrative instructions — Treatments authorized. — Pursuant 
to the authority conferred upon the Chief of the Bureau of Entomology and 
Plant Quarantine by subsection (a) of § 301.72-5, Chapter III, Title 7, Code 
of Federal Regulations [Regulation 5 of Notice of Quarantine No. 72 on account 
of the white-fringed beetle], the following methods of treatment for plants in 
pots, or with soil balls, and potted soil, are hereby authorized effective Septem- 
ber 11, 1941, when carried out under the supervision of an authorized inspector 
of the United States Department of Agriculture. 
(a) Plants in pots or in soil balls. — (1) Methyl bromide fumigation at at- 
mospheric pressures. — (i) Fumigation must be done with methyl bromide at a 
dosage of 1 pound per 1,000 cubic feet, including the space occupied by the 
plants, for a period of 4 hours, the soil masses and the air in the fumigation 
chamber to be at a temperature of not less than 85° F. 
(ii) Such fumigation shall apply only to those plants in 3-inch pots or 
smaller, or in soil balls not greater than 3 inches in diameter when spherical 
or thicker than 3 inches if not spherical, and the plants shall be stacked on 
racks so that the gas mixture can have access to all sides of the pots or the 
soil balls. 
(iii) The fumigation shall be done in a tight chamber with gas-tight doors. 
(iv) After the chamber is loaded and closed, the appropriate amount of methyl 
bromide shall be volatilized therein, and the air-gas mixture shall be 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° F. or above, and the 
diameter 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 
vaporized 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. 
(b) 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 de- 
natured 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. 
2 Superseding §§ 30l.72-5a and b. 
