64 
PLANT QUARANTINE AND CONTROL ADMINISTRATION [April-June, 
pest. In view of this fact and of the limited distribution of the pest in the 
United States, it is desirable to prevent its artificial dispersion as much as 
possible. As nursery products are shipped to distant points, they are among 
the most dangerous agencies for dispersing the pest. 
Research has been conducted at the Japanese beetle laboratory for over eight 
years to develop methods for treating nursery products so that they can be 
shipped into uninfested areas without danger. Most of this work has been 
done in cooperation with the nurseryman immediately concerned with the 
product to be shipped. Because of the cooperative nature of the work it has 
been possible to obtain a large amount of information on some varieties while 
it was possible to obtain only a limited amount of data on others. 
This paper is prepared with the object of presenting the latest technical in- 
formation on the disinfection of various nursery products infested with the' 
immature stages of the Japanese beetle. The term " disinfection " in this paper 
means the destruction of the immature stages of the beetle by physical or chem- 
ical treatments. 
Introduction. — The information is presented, for convenience, under the fol- 
lowing headings : 1. Disinfection of soil in the absence of plants. 2. Disinfection 
of soil about the roots of plants. 3. Directions for treating the different nursery 
plants. 
2. DISINFECTION OF SOIL IN THE ABSENCE OF PLANTS 
Infestation may occur in potting soil, in soil plots used for bedding plants, 
in frames, and on greenhouse benches. The following methods have been de- 
veloped for disinfecting soil under these conditions. 
A. Disinfection of Potting Soil 
Infested potting soil may be disinfected by fumigation with carbon disulphide 
or with naphthalene, or by heat treatment. All of these tretments are effective 
and do not impair the soil fertility when applied as recommended. 
A. 1. Fumigation of potting soil with carbon disulphide 
Material. — A technical, C. P., or U. S. P. grade of carbon disulphide should be 
used to fumigate soil in which plants are to be grown. Caution. Carbon 
disulphide is a dangerous chemical. The vapor is inflammable, and is explosive 
when mixed with air. At a temperature of 297° F. it will take fire spon- 
taneously. It should be kept away from fire of all kinds, and from hot objects 
such as electric light bulbs, heating coils, steam pipes, etc. Lighted cigars, ciga- 
rettes, or pipes should never be brought into the same room. These facts must 
be brought to the attention of a responsible person at the nursery before the 
treatment is applied to the soil. 
Equipment. — The fumigation must be done in a tight box or bin, which may 
be made of metal, wood, concrete, brick, stone, or other material providing the 
top, sides, and bottom are gas proof. It should be of a size adapted to the 
quantity of soil to be treated. Some convenient sizes for treating small quanti- 
ties of soil are shown in the following table : 
Table 1 
Capacity 
Depth 
Length 
Width 
Capacity 
Depth 
Length 
Width 
2 cubic yards 
3 cubic yards 
4 cubic yards 
5 cubic yards 
o cubic yards 
Feet 
3 
3 
3 
3 
3 
Feet 
6 
9 
9 
9 
9 
Feet 
3 
3 
4 
5 
6 
7 cubic yards 
8 cubic yards 
9 cubic yards 
10 cubic yards 
Feet 
3 
3 
3 
3 
Feet 
9 
12 
18 
18 
Feet 
7 
6 
4.5 
5 
Condition of soil. — Soil of any type may be fumigated with carbon disulphide, 
providing the soil is friable and is thrown loosely into the box. It should be 
dry or only moist ; wet soil must never be treated. 
Temperature. — The effectiveness of treatment with carbon disulphide de- 
pends, to a large extent, upon the temperature of the soil. The higher the 
