BUREAl* OF ENTOMOLOGY AND PLANT QUARANTINE 61 
The pollens from each fruit gave encouraging sets, although in vary- 
ing degrees. While wet and dry mixtures of the almond pollen gave 
comparable results, cherry pollen gave a lower set when applied in 
a sirup carrier than when applied in a dry carrier. 
Habits of Wild Bees Studied 
Studies of nesting sites and pollen stores revealed that alkali bees 
(Nomia melanderi Ckll.) in one place flew at least 2 miles to get alfalfa 
pollen, and that bees from one place collected rabbitbrush pollen but 
bees from another did not, rabbitbrush being equally abundant in 
both places. 
New Bee Disorder Found 
In certain samples of dead brood received for diagnosis from Mary- 
land, Pennsylvania, New Jersey, and Virginia, all the brood had ap- 
parently died from the same cause. Affected brood was light yellow. 
Some of the dead larvae were in uncapped cells; they had assumed 
curled, twisted positions. Many were in capped cells, the cappings 
being perforated, as is common in American fonlbrood. The dead 
larvae were easily removed from both capped and uncapped cells. 
Keversed brood was found in some cells. Examinations failed to 
reveal the presence of a causative microorganism or virus. 
New Insecticides Found Dangerous to Pollinating Insects 
Toxaphene dust and spray showed low toxicity in field tests to 
determine the effect on honey bees of dusts and sprays of DDT, chlor- 
dane, and toxaphene applied to alfalfa in bloom, conducted in co- 
operation with the Utah Agricultural Experiment Station. The 
applications were made before 7: 00 a. m. No mortality from DDT 
spray at 0.5 pound an acre was observed, but mortality from DDT dust 
at 0.5 pound an acre was estimated at 5.5 percent. Chlordane spray 
gave a 10-percent mortality in one test and a 26-percent mortality in 
a second test. The mortality from chlordane dust was estimated at 
only 3.6 percent. Chlordane dust, although causing light mortality 
in this series of tests, had given erratic results in the past. The 
greater kill from chlordane spray is in line with previous results and 
indicates that they are more toxic to bees than chlordane dusts. 
Observations following widespread application of parathion and 
less extensive treatments with TEPP to combat a severe outbreak of 
pea aphis in the Delta area of Utah showed that the main field forces 
of at least one-third the 14,000 bee colonies in the tract were killed by 
the insecticides. 
Bees May Have Physiological Resistance to American Fonlbrood 
In tests on resistance to American fonlbrood, combs containing eggs 
from queens of various strains were given to a heavily diseased colony 
for hatching and rearing to the sealed-brood stage. The sealed brood 
was then transferred to an incubator to prevent removal of any dis- 
eased brood. The amount of disease found in the brood of the differ- 
ent strains showed a fail- correlation with the mortality observed in 
colony-inoculation tests. This variation in the devolpnient of Amer- 
