12 BULLETIN 1332, U. S. DEPARTMENT OF AGRICULTURE 
Three similar lots, each of 12 plants, were dug after the first heavy 
frost and immersed for periods of 6, 9, and 12 hours, respectively, 
in a dip containing 1 cubic centimeter of ascaridole to 6 liters of 
water. The roots had not previously been trimmed, but, after dip- 
ping, the roots were cut on and divided into lj^-inch pieces and 
planted in a coldframe. They developed normally in the spring, but 
were somewhat slow in beginning growth. The roots of the plants 
of three other similar lots, each of 12 plants, were trimmed and cut 
into pieces, after which both plants and root cuttings were immersed 
in a dip like that for the other three lots and for the same periods, 
respectively. These root cuttings were planted in the same manner 
as those of the other three lots and made the same growth in the 
spring. The mature plants of all six lots were placed in cold storage 
until February 1, when they were potted and placed in the green- 
house, where their growth was equal to that of the controls and in 
many cases superior. 
Still other plants were removed from cold storage February 1 and 
three lots, each of 12 plants, immersed for 6, 9, and 15 hours, respec- 
tively, in a dip containing, as before, 1 cubic centimeter of ascaridole 
to 6 liters of water. Twenty-four hours after removal from the dip 
these plants were potted and placed in the greenhouse. Their 
growth there was superior to that of the controls. 
TREATMENT OF SEDUM SPECTABILE 
The showy sedum, Sedum spectabile, has a coarse, matted root 
system and is frequently infested with the larvae of the Japanese 
beetle. To test the efficacy of wormseed oil as a protective dip, four 
lots, each of six plants of this species, were dug in the early spring, 
the surplus soil adhering to the roots removed by shaking, and the 
four lots immersed for 12, 15, 18, and 24 hours, respectively, in a dip 
of wormseed-oil emulsion containing 1 cubic centimeter of ascaridole 
to 6 liters of water and at a temperature of 70° F. All came through 
the treatment without injury to the roots. At the time of dipping, 
the plants had made about 3 inches of top growth. This was injured 
by the clip and sloughed off, but on potting the plants and placing 
them in the greenhouse, the treated plants soon threw out new top 
growth and prospered, soon catching up with the controls. 
VALUE OF WORMSEED OIL AS AN INSECTICIDE 
The results of the experimental work which has been described in 
the preceding pages indicate that a dip the insecticidal basis of which 
is wormseed-oil emulsion is, under certain conditions, a reliable 
destroyer of the larvae of the Japanese beetle, though not rapid in its 
action. Of all the compounds tested for this purpose it is the least 
toxic to plants. The cost of treatment with this insecticide is not 
prohibitive; 1 pound of wormseed oil; assaying 75 per cent ascaridole, 
will make 500 gallons of dip. It seems probable that this treatment 
could be utilized in many similar cases of needed control of insects. 
TREATMENT OF PEONY ROOTS 
Figure 2 represents a typical peony root, the root cavity being split 
open to show its characteristics as a hiding place for the larvae of the 
Japanese beetle. In the majority of peony roots the cavities contain 
more or less soil, usually compact and in one solid mass; whereas in 
iris the soil is interspersed in very small individual amounts through 
