BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 73 
which heavily infested imported tobacco had just been removed. In 
such instances, even though American tobacco has been fumigated 
prior to export, it is subject to infestation during transit. 
Inspections of railroad cars indicate that many moths are trans- 
ported to the storage warehouses and ports along with the tobacco. 
Moths carried in this manner are capable of starting new infesta- 
tions in tobaccos that have recently been fumigated, as well as in 
recently cured tobacco, en route to storage warehouses or ports. 
TOBACCO MOTH AND CIGARETTE BEETLE IN STORED TOBACCOS 
The effectiveness of pyrethrum powder, applied at weekly inter- 
vals in open-storage tobacco warehouses, for controlling adults of 
the tobacco moth was further studied. Several important limita- 
tions to its use were noted, such as the slow reduction in populations, 
the undesirable coating of pyrethrum powder on the hogsheads at the 
end of the season, the large number of eggs laid by the female moths 
after the dusting, and the fact that pyrethrum does not kill the 
eggs, larvae, or pupae of the moth. 
Experiments with the fumigation of tobacco with hydrocyanic 
acid gas at reduced pressures showed that complete mortality of 
the tobacco moth and cigarette beetle was obtained under summer 
conditions, whereas unsatisfactory controls were obtained under win- 
ter conditions. Tests in the fumigation of open-storage warehouses 
temporarily sealed showed promising results when dosages of 6 and 
8 ounces of the hydrocyanic acid per 1,000 cubic feet were used, with 
an exposure of 24 hours. 
THE TOBACCO FLEA BEETLE 
Experiments on the control of the tobacco flea beetle in plant beds 
in South Carolina showed that paradichlorobenzene was not an effec- 
tive remedy against this pest. The material was applied daily by 
spreading it on a shelf attached to the inside of the board side walls 
of the bed at rates up to 2 ounces per square yard of plant bed. Addi- 
tional tests with insecticides showed that a dust mixture containing 
1 percent of rotenone or a cryolite dust mixture containing 80 percent 
of sodium fluoaluminate gave good protection of the plants from injury 
by the tobacco flea beetle. However, the cryolite gave the best protec- 
tion over a period of 6 days. 
A study of the seasonal habits of the tobacco flea beetle on flue- 
cured tobacco showed that heavy infestations of this pest may kill 
the newly transplanted tobacco or damage it to such an extent that it 
will be slow in becoming established and beginning growth. The 
infestation on newly set tobacco may also be an indication as to the 
subsequent intensity of beetle infestation and damage on the tobacco 
approaching maturity. The studies showed also that newly trans- 
planted tobacco, particularly in the Piedmont area of North Carolina 
and Virginia, is infested by the beetle at two separate periods, first, 
soon after transplanting and again in about 2 or 3 weeks. The first 
infestation is by overwintered beetles, while the second is by beetles 
from the new generation coming from sources outside the field. 
Although the beetle breeds on several species of plants, the only ones 
found to be of any great importance are tobacco, potato, tomato, and 
