BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 19 
Sweetpotato Weevil Control 
Sweetpotato planting restrictions, originally imposed because of 
sweetpotato weevil infestations, were removed from 2,050 farms after 
thorough inspections failed to locate any further infestation. First- 
record infestations of this most destructive pest of sweetpotatoes were 
found on 1,140 properties throughout the infested area. Suppressive 
control measures were applied on 20,000 farms in 6 Louisiana parishes. 
Only half as many infested properties were found in 1951 as in 1950. 
Active infestations were reduced by 20 percent in the infested parts of 
Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, 
and Texas. 
DDT dusting of seed sweetpotatoes in the control areas of Louisiana 
progressed to the extent that approximately 80 percent of the growers 
applied this treatment. 
Bureau personnel continued to assist infested States in the enforce- 
ment of quarantines to prevent the spread of the weevil to noninf ested 
areas or its reintroduction into areas from which it has been eradi- 
cated. Weevil infestation in sweetpotatoes intended for shipment has 
been greatly reduced by more effective cultural methods, together with 
enforcement of sanitary procedures and DDT spraying at kilns and 
packing sheds. Certified shipments from Louisiana alone during 1951 
totaled approximately 6 million bushels. Fewer violations of the 
State regulations were reported, indicating a greater public acceptance 
of the precautionary requirements. 
Curly-Top Disease in Beans Reduced by Killing Beet Leafhoppers 
on Wild Hosts 
Research was started in 1948 to determine whether the seed bean 
crop in southern Idaho can be protected from curly-top disease by 
controlling its vector, the beet leaf hopper. This leaf hopper concen- 
trates and develops on weed host plants growing on the desert and on 
idle and waste lands. The work was done in cooperation with the 
Idaho Agricultural Experiment Station with funds authorized under 
the Research and Marketing Act. 
Host-plant surveys were made in southern Idaho during the fall of 
1950 and early spring of 1951. These surveys indicated that approxi- 
mately 6,300 acres of weed host plants were infested by the beet leaf- 
hopper to an extent that made this acreage potentially dangerous as 
a source of infestation by adults migrating to adjacent or nearby bean 
fields. Consequently, this entire acreage was sprayed during the 
period April 28 to June 9, 1951, with a concentrated emulsion spray 
containing DDT. The spray was applied with turbine blowers, 
equipped with side-delivery nozzles, mounted on trucks, at the rate of 
approximately 2 gallons per acre, which gave about 0.6 pound of DDT 
per acre. A post-treatment survey disclosed that beet leaf hopper 
numbers in the weeds had been reduced about 93 percent. Examina- 
tions in southern Idaho during mid-season of fields of garden beans 
grown for seed showed that the number of bean plants infected with 
curly-top disease had been reduced from an expected 12 percent to 
an observed 3.9 percent. This percentage was calculated from an index 
