﻿28 BULLETIN 1364, V. S. DEPARTMENT OF AGEICULTUEE 



year (1919) three trees were caged with wire screen, of which one 

 was sprayed and one dusted, as in the first year, the third used as a 

 control, and a normal colony of bees, with ample stores, placed in 

 each of the three inclosures. Dead bees, collected from the cages, 

 were counted and analyzed for arsenic in the laboratory. Three 

 trees in full bloom in the open were also sprayed, Avhile more than 

 200 were left unsprayed; live bees were counted on the sprayed 

 blossoms and dead bees analyzed. In spite of the criticism that 

 might be made in regard to the methods employed of confining bees 

 with trees in large cages and of confining them singly in glass 

 funnels when testing for fatal doses of arsenic. Price's conclusions 

 are not far different from those reached in the present investigation. 

 Less than 0.0005 milligram of arsenious oxide (AsgOg) was found a 

 fatal dose for a bee. The longevity of bees poisoned with arsenic 

 was found to depend upon the size of the dose; some died within 

 1^ hours, others lived 5 or 6 hours, and most of those poisoned in 

 the field died within 3 hours. Bees worked freely on sprayed trees 

 in the open, even when there were unsprayed ones near by. The 

 mortality of the bees in the control cage was 19 per cent, as com- 

 pared with 69 per cent in the cages containing the trees sprayed with 

 lime-sulphur and lead arsenate, and 48 per cent in the cage contain- 

 ing the tree dusted with sulphur and lead arsenate. 



Doane (S) sprayed an apple tree, almost in full bloom, and then 

 covered it with a cage. Two days later he placed a colony of bees 

 inside this cage, and the following morning, while the bees were 

 confined in their hive, the tree was again sprayed. He claims that 

 these bees worked in an apparently normal way and were not injured 

 by the arsenical spray material. This experiment was repeated, 

 using another tree and another hive of bees, and similar results were 

 obtained. His chemist reported for the small num.ber of bees col- 

 lected and analyzed that the dead bees collected in the cage at the 

 end of the first experiment contained 0.0025 milligram, those col- 

 lected alive during the first experiment 0.002 milligram, and those 

 found dead during the second experiment 0.0006 milligram, respec- 

 tively, of arsenic per bee. According to the results obtained by the 

 present writers, less than these amounts of arsenic would, if eaten, 

 have killed the bees. The next spring Doane repeated his experiments 

 on a slightly larger scale, and finally concluded that spraying in full 

 bloom under California conditions is not injurious to honeybees. 



Merrill (-/i), while not repeating Doane's experiments, severely 

 criticizes his methods, and compares his results with those obtained 

 by Price, concluding that the latter were more likely to be correct. 



SUMMARY 



In the preliminary experiments conducted at Winchester, Va., 

 1914, three small, more or less isolated orchards were selected, and 

 three strong colonies of bees were installed in each orchard. Twenty- 

 five trees were spraj^ed in each orchard, the first 25 with a mixture of 

 Paris green, the second 25 with a mixture of paste lead arsenate, and 

 the third 25 with a mixture of paste lead arsenate and lime-sulphur. 

 The following results were obtained: (1) Bees work equally as well 

 on trees sj^rayed in full bloom as on unsprayed ones; (2) they do not 

 fly away from the sprayed orchard very much if the orchard is well 



