74 ANNUAL REPORTS OF DEPARTMENT OP AGRICULTURE, 1 
Gray, a malvaceous plant closely related to cotton. The comi ercial | 
cotton began In the Santa Cruz Vall< L918, and In September i'.':: 1 * the 
first Infestation of the w< evil was found In cultivated cotton. 
then light infestations have been found. The infested Tl 
1 1.\ in tuntain ranges furnish a consl 
and i" remove this menace 11 was decided to attempt the eradicatioi 
plants, i: relief funds were provided by the v. Adsninis 
tration. 
Ac ive work was begun on August 20, 1935. A few men were first trained as 
ps, and after the necessary equipment waa the labor 
200. Work was begun in th • Tortillita 8 
northwesl of Tucson, which is the range oearesl to cultivt ton. Work 
(Hi i! was completed on February 14, L936, 64,680 a< • 
over and 59,283 Tliurberia plants destroyed. Thes< ranged in size 
from seedlings just a Pew inches high to plants as high as 12 Ceet. They UEuallv 
occur in small colonies. The oext nearesl range is the Santa Catalina Mountains, 
and a tely begun in this range, which is much rougher Thar 
the Tortillitas. A1 times il was Deeessary to lower- men with ropes from 600 
to 800 feel from the top of a cliff to ledges where plants occurred. Plants were 
much more numerous in this range, and mosl of them were infested with t lie 
11. At the close of the fiscal year 38,560 acres bad been covered in the 
Santa Catalinas and 554,607 plants destroyed. The above acreage consists of a 
strip about '2 miles wide extending from the southwest corner of the range about 
1) miles northward along the westward slope and about IT miles eastward 
the soul hern slope. 
Laborers are transported from Tucson each morning to the mountains and 
returned to Tucson at the end of the day. To do this highways are used as far 
.•i-- possible, but in order to gel through the foothills and onto the ranges it has 
been necessary to do considerable work on the trails before they wei 
the trucks to pass over. It was necessary to construcl new trails in seme ; 
so that the men could be transported as near the place they were to work as 
possible. 
BEE CULTURE 
Headquarters for the Division of Bee Culture were moved from Somerset, 
Md., to the National Agricultural Research ('enter. Beltsville, Md., where, in 
addition to the administrative work, research is in progress. 
Colonies of Caucasian, Carniolan, common black, and Italian bees inoculated 
with European foulbrood all became infected. Pure Caucasian bees, however, 
cleaned out the disease more quickly than did the other races. Common black 
bees were the least active in doing so. 
Bacillus larvae, a bacterium that causes American foulbrood, was found to 
: ?s a remarkable resistance to beat. Spores of this organism were viable 
in culture after having been boiled in water tor i hours at Beltsville. This 
is contrary to the belief that boiling in water for a tew minutes kills the spores. 
They were also viable after having been subjected to dry heat at ii*» c. for 
ys. 
During the year 838 samples of comb, brood, and adult bees were received 
for diagnosis. Very few samples of treated combs were received for sterility 
Indicating thai beekeepers are not attempting to save infected combs to 
i ;nt they were ;i few years ago. 
Ten samples of honey taken from supers of colonies infected with American 
foulbrood and three samples of commercial honey from slightly infected apiaries 
fed to healthy colonies. The number of spores in the samples ranged 
from 28,000 to ubic centimeter, all being close to the border line 
of Ihe minimum Infectious dose of l liter ><\ sugar sirup containing 50.000 
per enhie centimeter. Two colonies developed disease and two others 
showed a slight Infection, which later disappeared. 
i cooperation with the University of California, an analysis <<f 60 western 
crude beeswaxes showed a great variation in physical and chemical constants 
opared with Blight variations In the constants of virgin beeswaxes. The 
e variations appears to be the content of impurities. The wax 
nts give little Indication as to the suitability of ••rude waxes (<<r bleaching 
inlight, absorption, or chemical reagents. The most common soluble im- 
purities i!' beeswai are apparently pollen components, iron stains, and propolis, 
having appreciable quantities of propolis can be bleached only with 
