BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 49 
grain for a period of 6 hours at a temperature of 95° F. However, 
at a temperature of 50° F. wheats containing any normal degree of 
moisture can safely be fumigated with chloropicrin at dosages of from 
1 to 6 pounds to 1,000 bushels of grain for periods not exceeding 12 
hours. 
Observations during the year have shown methyl bromide to have 
considerable promise as a cheap and efficient fumigant for flour mills 
and stored rice. A recent fumigation of a large warehouse containing 
3,500,000 pounds of rice with methyl bromide at a dosage of 4.85 
pounds to 1,000 pounds of rice gave a complete kill of the contained 
insect pests within a period of 42 hours at a temperature of 87° F. 
WHITE-FRINGED BEETLE CONTROL AND ERADICATION 
Observations on the results of control and eradication measures 
applied against the white-fringed beetle (Pantomorus levxyoloma 
(Boh.)) and a closely related species, P. peregrinus (Buch.), indi- 
cate the effectiveness, as a means of reduction in beetle population, 
of calcium arsenate dust on host plants, of an oil-base emulsion as 
an herbicide to eliminate host vegetation along railroad rights-of- 
way, roadsides, abandoned fields, and waste areas, and of clean- 
cultivation practices in crop areas. 
Such practices, which were an important part of the 1938 program, 
were continued and their application was extended so that one or a 
combination of such methods of control was used on all known in- 
fested properties. While there has not been sufficient time to fully 
determine the effectiveness of such types of control, field observations 
indicate drastic reduction in beetle population, though to a somewhat 
lesser degree in fields where legumes were planted and where cryolite 
was substituted for calcium arsenate, because of the detrimental 
effect of the latter insecticide on such plants. During the latter 
part of the year excessive precipitation made the application of con- 
trol measures difficult. 
One of the important phases of the program designed to prevent 
the spread of the pest was the enactment of a Federal domestic 
plant quarantine effective January 1, 1939. The regulations were 
strictly enforced. This quarantine is supplemented by State quar- 
antine measures which place restrictions on intrastate movement of 
host materials. Intensive surveys were conducted to delimit known 
infested areas and to determine whether the pest had spread to other 
parts of the infested States and to other Southern States. No in- 
festations were found in any State in which the beetle had not been 
previously known to exist. During the year infestations were found 
in the following areas : 
Alabama : Covington, Geneva, Monroe, Conecuh, Mobile, and Wilcox Counties. 
Florida : Okaloosa, Walton, and Escambia Counties. 
Louisiana : St. Bernard, Orleans, Jefferson, East Baton Rouge, Plaquemines, 
and Jeff Davis Parishes. 
Mississippi: Jones, Harrison, Stone, Smith, Covington, Jackson, Hinds, Pear] 
River, and Forrest Counties. 
The total infested areas comprise approximately 50,000 acres, a 
large portion of which is idle, forest, waste, or abandoned land. 
188590—40 4 
