66 PLANT QUARANTINE AND CONTROL ADMINISTRATION [April-June, 
this method, follow the detailed instructions given on a previous page for the 
fumigation of potting soil with carbon disulphide. 
C. Disinfection of Soil in and Around Plots, Cold frames, Hotbeds, etc. 
Soil in and surrounding plots, coldframes, hotbeds, etc., which is used for 
plunging pots or heeling-in plants, must be disinfected by treatment with lead 
arsenate as prescribed in section C. 1. Under special conditions on specific 
authorization from the administrator in field charge of the Japanese beetle and 
Asiatic beetle project, fumigation with carbon disulphide, carbon disulphide 
emulsion, or naphthalene may be substituted for the temporary elimination of 
infestation. 
C. 1. Treatment with lead arsenate 
Material. — Use powdered acid lead arsenate. 
Condition of the soil. — The soil must be friable and in good tilth. 
Season. — Treatment must be applied before August 1 if the land is to be 
used that autumn. 
Dosage. — Lead arsenate must be applied at the rate of 1,500 pounds to each 
acre, or 35 pounds to each 1,000 square feet. 
Application. — Plow and harrow the soil until it is in good tilth. Mix the 
lead arsenate with ten times its volume of dry soil, sand, or other fillers, and 
apply with a fertilizer drill, or broadcast it by hand. Harrow the soil well, as 
a thorough mixture is essential. 
Period of treatment. — As lead arsenate is a stomach poison which has to be 
eaten by the larvse, it may take several weeks before all infestation is elimi- 
nated. Do not plant, heel in, or plunge plants in soil poisoned with lead ar- 
senate until at least eight weeks after treatment. 
C. 2. Fumigation with carbon disulphide 
Material. — A technical U. S. P. or C. P. grade of carbon disulphide should 
be used. Carbon disulphide is explosive ; observe the precautions on page 64. 
Equipment. — A tarpaulin or other air-proof cover must be provided, to cover 
the soil after treatment. 
Condition of soil. — Soil of any type may be treated providing it is friable. 
Wet soil must not be treated. 
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° F. before fumigation is complete, the treatment must be repeated. 
Weather conditions. — The ideal conditions for treatment are a warm, humid 
atmosphere without wind. 
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. 
Dosage. — Carbon disulphide must be used at the rate of 6 pounds or 2,100 
cubic centimeters to 100 square feet of soil surface. 
Application. — Carbon disulphide must be uniformly distributed throughout 
the upper 6 inches of soil. Apply it in holes 12 inches apart and 1 to 2 inches 
deep, putting 21 cubic centimeters in each hole. Fill each hole with soil im- 
mediately after the liquid is poured in. Complete the treatment as quickly 
as possible, covering each section with tarpaulin as soon as it is treated. 
Period of fumigation. — The soil must remain covered for at least 48 hours. 
C. 3. Treatment with carbon disulphide emulsion 
A fa I crial. — Only 35 per cent miscible carbon disulphide is to be used for this 
treatment. This must be prepared according to the formula recommended by 
the Japanese beetle laboratory and published in the Journal of Industrial and 
Engineering Chemistry, volume 20, pages S49-S50, August, 1928. Miscible 
carbon disulphide when diluted with water forms an emulsion. Caution. 
Miscible carbon disulphide and carbon disulphide emulsion are infiammable. 
Sec caution on page G4. 
Equipment.- -Twenty-four*gage galvanized-iron collars 10 inches wide and 
not more than -1 feci square arc needed Tor applying the emulsion. Suitable 
tanks, barrels, or tubs for preparing the solution should bo provided. 
Condition of soil.— Any type of soil may be treated by this method. The 
surface must he level and not disturbed by recent cultivation. The drainage 
