1934] 
SERVICE AND REGULATORY ANNOUNCEMENTS 
3 
Application to soil. — Any quantity of soil may be fumigated, providing the 
carbon disulphide is distributed uniformly throughout. One method is to fumi- 
gate the soil while the box is being filled. Place 18 inches of soil loosely in the 
box. Inject carbon disulphide at the rate of 176 cubic centimeters for each 
square yard of surface, distributing the material uniformly in holes 2 inches deep 
and 18 inches apart, 44 cubic centimeters to each hole. Fill the holes with soil 
immediately after the liquid is injected. When the first 18 inches of soil has 
been treated, put in 18 inches more, and fumigate it the same as the first. This 
can be repeated until the container is filled. 
Another method is to fumigate the soil after the box has been filled. This 
is done by making holes from the surface to the different levels, so that the carbon 
disulphide can be applied in the same positions as by the other method. The 
liquid, in this case, must be poured into the deep holes through a tube, or injected 
to insure its reaching the proper level. 
Period of fumigation.— The container must be sealed, and left undisturbed 
for at least 48 hours. 
Storage of soil. — The soil must be stored under such conditions as will prevent 
reinfestation. 
A. 2. Fumigation of potting soil with naphthalene 
Material. — Flake naphthalene free from tar must be used for fumigation. 
Caution. — Naphthalene will burn. It must be kept away from fire. 
Equipment. — It is not necessary to have a special fumigation box in which to 
fumigate soil with naphthalene. 
Condition of soil. — Dry or moist soil of any type may be fumigated with 
naphthalene. Wet soil cannot be fumigated satisfactorily. 
Temperature. — The effectiveness of the treatment depends to a large extent 
upon the temperature of the soil. The higher the temperature the more effective 
is the fumigation. The temperature must never be allowed to fall below 50° F. 
Dosage. — Five pounds of flake naphthalene must be used to a cubic yard of soil. 
Mixing. — The success of the fumigation depends to a large extent upon the 
thoroughness with which the flakes are mixed with the soil. Spread the flakes 
on the soil and mix thoroughly by shoveling over at least three times. 
Period of fumigation. — Soil must be left undisturbed for a week after fumigation. 
Storage of soil. — The soil must be stored under such conditions as will prevent 
reinfestation. 
A. 3. Treatment of potting soil with steam 
Equipment. — It is necessary to have a boiler that will generate an ample 
supply of steam, and equipment for properly dispersing the steam throughout 
the soil. 
Condition of soil. — Soil of any type may be treated with steam, providing it is 
friable. 
Temperature. — The soil must be heated throughout to a temperature of 130° F. 
Period of treatment. — The soil temperature must be maintained at 130° F. for 
30 minutes after it has reached this temperature throughout the mass. 
Storage of soil. — After treatment with steam, soil must be so stored and handled 
as to prevent reinfestation. 
A. 4. Treatment of potting soil with lead arsenate 
Material. — Powdered acid lead arsenate. 
Condition of soil. — The soil to be treated must be in a friable condition.. Wet 
soil cannot be treated satisfactorily. The treatment is recommended only for 
soils which are slightly acid or neutral in reaction. 
Season. — Lead arsenate must be applied before August 1. When plants potted 
in soil treated as prescribed are carried over until the following year, they may 
be again eligible for certification between October 1 and the following June 15 of 
the second year if, on August 1 of the second year, analyses show the soil to con- 
tain lead arsenate at the rate of 2 pounds per cubic yard. This treatment cannot 
be relied upon to eliminate the infestation in the soil if applied in the fall or in 
the spring when the larvae are fully developed. It is important to have poison 
in the soil at the time the eggs are hatching. 
Dosage. — Acid lead arsenate must be used at the rate of 2 pounds to each cubic- 
yard of soil. 
Application to soil. — The lead arsenate must be uniformly mixed with the soil. 
This may be accomplished either by hand shoveling or by the use of a machine 
