6 
BUREAU OF PLANT QUARANTINE 
[Jan. -Mar. 
Equipment — Twenty-four-gage galvanized-iron collars 10 inches wide and not 
more than 4 feet square are needed for applying the emulsion. Suitable tanks, 
barrels, or tubs for preparing the solution must be provided. 
Condition of soil. — Any type of soil, providing it is friable, may be treated by 
this method. Wet soil cannot be treated satisfactorily. The surface must be 
level and not disturbed by recent cultivation. The drainage conditions of the 
soil are important. The solution must not disappear from the surface in less than 
10 minutes, and must be absorbed by the soil within 5 hours. 
Temperature. — The temperature of the soil 6 inches below the surface must be 
at least 45° F. when the treatment is applied. If the temperature falls below 40° 
before the treatment is finished, the soil must be treated again. 
Season. — Treatment must not be applied when adult beetles are present. An 
exception may be made in the case of plots that are protected from beetles. 
Dosage. — The dilution depends on the soil temperature; follow table 2 of sec- 
tion 2, D. Use 2H gallons of the dilute emulsion to each square foot of soil, as 
in table 4 of section 2, D. 
Application. — Level the surface of the ground, removing weeds and debris. 
Force a galvanized-iron collar 3 inches into the soil, and firm the soil against the 
metal. Place another collar next to the first, and so on. When enough collars 
are in place, pour the dilute carbon disulphide into the basins formed within the 
collars. As soon as the liquid has disappeared from the surface, the collar may 
be lifted and set in another position. 
Period of treatment. — The soil must not be disturbed for 48 hours after treatment. 
Safety zone. — Same as that prescribed in 1, C. 1. 
Marking. — Same as that prescribed in 1, C. 1. 
C. 4. Fumigation with naphthalene 
Material. — Flake naphthalene free from tar. Caution: Fire should be kept 
away from naphthalene. 
# Condition of soil. — Any type of soil may be treated with naphthalene provided 
itfcis friable and in good tilth. Wet soil must not be treated. 
Season. — The treatment must not be applied when adult beetles are present. 
An exception may be made in the case of plots that are protected from beetles. 
Temperature. — To be effective the temperature of the soil at a depth of 6 inches 
must not be less than 50° F. for a week after fumigation. 
Dosage. — Naphthalene must be used at the rate of 2,000 pounds per acre, or 
approximately 46 pounds per 1,000 square feet. 
Application. — The naphthalene must be uniformly distributed over the surface, 
worked in, and thoroughly and uniformly mixed with the soil to a depth of 3 
inches. 
Period of fumigation. — The land must not be disturbed for 1 week after fumi- 
gation. 
Safety zone. — Same as that prescribed in 1, C. 1. 
Marking. — Same as that prescribed in 1, C. 1. 
2. TREATMENT OP SOIL ABOUT THE ROOTS OF PLANTS 
A. Removing infestation by shaking, or washing with water 
The roots of some plants can be made entirely free from soil, either by shaking 
or washing. 
Washing all soil from the roots of the plants with water is probably one of the 
most simple methods for removing the infestation from certain varieties of plants. 
The method has certain disadvantages in that it is dependent for its effectiveness 
almost entirely upon the vigilance and the determination of the inspector in mak- 
ing sure that all soil is washed from the roots and that no tangled mass of roots 
or cavity hides a larva. 
Condition of plants. — The plants should be in a dormant or semidormant con- 
dition. Only such root masses as can be thoroughly examined and the absence of 
infestation verified should be certified under this procedure. Plants must be 
protected from possible reinfestation. 
B. Treatment with hot water 
Equipment. — It is necessary to have a water tank equipped with a suitable 
heating device, and a system for circulating the water in order to maintain a 
uniform temperature. 
Condition of plants. — Plants are usually most resistant to hot water when they 
are dormant, and most susceptible when they are growing vigorously. It is 
