5Q BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE [Apr.-June 
(Jc) Soil in and Aeound Coldframes, Plunging Beds, and Heeling-in Areas 
Soil in and surrounding coldframes, plunging beds, heeling-in areas, etc., 
must be treated with lead arsenate, except, under special conditions, when the 
inspector may authorize the use of heat, carbon disulfide, carbon disulfide emul- 
sion, or naphthalene. With the exception of lead arsenate, the treatment must 
not be applied when adult beetles are present. An exception may be made in 
the case of beds protected from beetles. 
Safety zone. — -In addition to the area desired to be certified, a strip 3 feet 
wide must be treated around the entire coldframe, plunging bed, or heeling-in 
ground. No plants will be certified from this strip. In the case of coldframes, 
etc., extending into the ground to a depth of 12 inches or more, no safety zone 
is required. 
Marking. — In the case of coldframes, etc., having fixed boundaries, proper 
designations will be made on them by the Department representatives. In all 
other cases the nurseryman shall furnish suitable stakes, at least 4 inches 
square and 30 inches long, to be placed at the boundaries of the certified plots 
and marked by the Department. 
( 1 ) LEAD AE SENATE TREATMENT 
Season. — The treatment must be applied before August 1 if the land is to 
be used in the fall. 
Condition of soil. — The soil must be friable and in good tilth. 
Dosage. — Thirty-five pounds to each 1,000 square feet, or 1,500 pounds per 
acre. For subsequent re-treatments, the quantity required to restore the original 
concentration, as determined by chemical analyses, must be applied. 
Application. — The lead arsenate must be thoroughly mixed and incorporated 
with the upper 3 inches of soil. 
Period of treatment. — Plants must not be placed on or in the soil thus treated 
until after October 1. 
{2) HEAT TEEATMENT 
Hotbeds, equipped with steam pipes or electrical resistance coils in the soil, 
may be treated by heating the soil to at least 130° F. and maintaining this tem- 
perature for 30 minutes. 
(3) CAEBON DISULFIDE FUMIGATION 
Equipment. — A heavy paper or other gasproof cover must be provided to 
cover the soil during the fumigation period. 
Condition of soil. — The soil must be friable and in good tilth. A wet soil 
must never be treated. 
Temperature. — The temperature of the soil at a depth of 6 inches must be 
at least 45° F. when the fumigant is applied, and must not fall below 40° during 
the period of treatment. 
Weather conditions. — The ideal conditions are a warm, humid atmosphere 
without wind. 
Dosage. — Six pounds (2,100 cubic centimeters) to 100 square feet of surface. 
Application. — Carbon disulfide must be uniformly distributed over the surface 
of the bed, plot, or heeling-in area. Apply it in holes 12 inches apart and 1 
to 2 inches deep, putting 21 cubic centimeters into each hole. Fill each hole 
with soil immediately after the liquid is poured. Cover each section as soon 
as the fumigant is applied. 
Period of treatment. — The soil must remain covered for 48 hours. 
(4) CAEBON DISULFIDE EMULSION TEEATMENT 
Equipment. — Suitable tanks, barrels, or tubs for preparing the emulsion and 
24-gage galvanized-iron collars 10 inches wide and not more than 4 feet square, 
for applying the treatment, must be provided. 
Condition of soil. — The soil must be friable. The surface must be level and 
not disturbed by recent cultivation. Drainage conditions must be such that the 
solution does not disappear from the surface in less than 10 minutes or more 
than 5 hours. 
