52 BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE [Apr .-June 
suitable containers, provided the water can circulate through the masses. Large 
plants must be placed individually in the water. 
Care of plants after treatment. — Plants should be cooled slowly to room 
temperature. Pot or heel them in the ground as soon as possible after cooling. 
Tubers should be dry when packed. Avoid subjecting treated plants to freezings 
temperatures shortly after treatment. 
(3) CARBON DISULFIDE EMULSION DIP 
Equipment. — Watertight tanks or tubs must be provided. 
Temperature. — The temperature of the dip must be maintained between 65° 
and 70° F. 
Dosage. — Forty -five cubic centimeters of carbon disulfide emulsion to 10 
gallons of water. The treating solution must be prepared immediately before 
using. 
Application. — The root masses must be immersed completely. 
Period of treatment . — The root masses must be immersed 24 hours. 
Varieties of plants. — The varieties which have been treated successfully by 
this procedure are given in Technical Bulletin 478. 
Preparation of plants. — Large clumps should be divided as much as possible 
without injuring the roots. Excess soil should be removed. No wet root 
masses or root masses measuring more than 6 inches across the narrowest 
dimension must be treated. The temperature of the root masses must be at 
least 60° F. before treatment. Small plants and root stocks may be packed 
loosely in wire baskets or other suitable containers, provided the dipping solu- 
tion can circulate through the masses. Larger root masses must be placed 
individually in the dip. 
Care of plants after treatment. — Tubers should be dry when packed. Avoid 
subjecting treated plants to freezing temperatures shortly after treatment. It 
is advisable to allow plants which are to be potted to stand in the open to per- 
mit evaporation of the fumigant before placing them in soil. 
(4) PARADICHLOROBENZENE FUMIGATION 
Season. — The treatment must be applied between October 1 and May 1. 
Varieties of plants. — The following varieties of plants have been treated suc- 
cessfully by this procedure : Aquilegia sp. var. Mrs. Scott Elliott's hybrid, Anemone 
hupehensis, Artemisia- dracunculus, Azalea amoena, A. kaempferi vars. Cleopatra, 
Fedora, Othello, and Salmon Beauty, A. hinodegiri, A. obtusa kiusiana var. 
Coral Bells, Aster alpinus, Campanula medium, Ceratostigma plumbaginoides, 
Chrysanthemum sp., Dianthus caryophijllus var. Abbotsford Pink, Digitalis pur- 
purea, Eupatorium coelestinum. Helianthemum glaucum croceum, Iberis amara, 
Myosotis sp., Pachysandra terminalis, Phlox sp. var. R. P. Struthers, Santolina 
chamaecyparissus incana, Sedum acre, Sempervirum alberti, Stokesia laevis, 
Thymus serpyllum, Viola sp. vars. Jersey Gem and Rosina. 
Preparation of plants. — Excess soil should be removed and the mass reduced 
as much as possible without injuring the roots. The plant ball should be moist, 
but not wet. Pots must be removed from potted plants. When burlap on 
balled plant is of coarse weave, it may be left on the balls, but when it is 
closely woven, it must be removed. 
Preparation of plunging soil. — The paradichlorobenzene must be thoroughly 
mixed with a light sandy loam, or sand, which is moist but not wet, and free 
from lumps, stones, and debris. It must be mixed immediately before using. 
Care of plants during treatment. — If it is necessary to water the plants during 
the treatment to prevent desiccation, the operation must be limited to a light 
syringing, under the supervision of an inspector. 
Care of plants after treatment. — It is advisable to avoid excessive watering 
of the plants after treatment in order to permit any residual gas to escape from 
the plant balls. 
(0 Complete coverage 
Temperature. — The temperature of both the treating soil and the soil ball 
must not be less than 50° F. during the period of treatment. To prevent injury 
to the plants, it should not go above 65°. 
Dosage. — Ten pounds per cubic yard of mixing soil (6 ounces per cubic foot) 
for soil balls up to 6 inches in diameter at the narrowest dimension. Twenty 
