80 AXMWL REPORTS OF DEPARTMENT OF AGRICULTURE. I 
interesting, in thai frw or no mature Beed have fallen to the ground 
during the past sew ral years, and all seed thai germinated this season 
must have been from '2 to 7 years old. 
During the L938 season 34^205 acres were covered in southern Florida 
in the removal of mid cotton plant-. Practically all this acreage was 
gone <>ver t wire, and a great port ion of it was covered thn e I imes. A 
total of 46,103 plants with mature bolls were found and destroyed and 
1,409,438 seedling plant- removed. Only 2,043 sprout plants 
found during the season. 
THURBERIA WEEVIL CONTROL 
Tlit' area in Arizona now regulated on account of the Thurberia 
weevil include- ( ocbise and Santa Cruz Counties and parts of Graham, 
Pinal, and Pima Counties, this area also being regulated by the pink 
bollworm quarantine. During the greater part of this year eradica- 
tion work was carried on in the Santa Catalina Mountains from camps 
established at various point- throughout that mountain range. Dur- 
ing the Last few months, however. Thurberia eradication was carried 
on in the vicinity of Sahuarita and the Continental ranch in the Santa 
Cruz Valley and in the large canyons west of the Tucson-Nogales 
Highway, and laborers have been transported hack and forth from 
Tucson to work. During the fiscal year ended June 30, L938, 98,020 
acres were covered and 444.7l!o Thiurberia plants destroyed, bringing 
the total acreage covered since this work started to 298,170 and the 
number of plants destroyed to l.TG4.7f>*2. Funds to carry on this work 
are provided by Work Projects Administration allotments, together 
witli funds allocated by this Bureau. 
BEE CULTURE 
In the Bureau's cooperative program on American foulbrood, par- 
ticipated in by the Arkansas, Iowa. Texas. Wisconsin, and Wyoming 
Agricultural Experiment Stations, over TOO queens of resistant stock 
were reared by the Texas station during the spring of 1939 for dis- 
tribution to cooperating beekeepers. 
In 1938, when strains of bees were being tested for resistance t<» 
American foulbrood at the Bureau's Wyoming laboratory. 27 out of 
-{<> inoculated colonies which contained queens of the F 2 and F genera- 
tions either recovered or failed to contract the disease, whereas out of 
27 colonies headed by 14 queens from stock with an unknown history 
for disease resistance and \:\ from F, queens of stock showing resist- 
ance only L2 recovered or failed to contract the disease. The data 
show that an increase in resistance was obtained over that in 1987. 
Work by the Iowa Agricultural Experiment Station the same year 
w iih 1 1 1 Line-bred queens reared by the Texas stat ion also indicated a 
gain in resistance. This increase apparently was the result <d* selec- 
tive line breeding, although some undesirable characteristics, such as 
nervousness and ;i tendency toward irregular-spotted brood nests, seem 
also t<> have been intensified. 
The [owa station in 1938 distributed to commercial beekeepers vvv 
Texas reared queens of resistant stock. The Bureau's Wyoming sta- 
i ion dist ributea 667 similar queens in Colorado, Minnesota, and Wyo- 
ming. Cooperators reported less disease in this stock than in stock 
obtained from other sources. 
