﻿EFFECTS ON HONEYBEES OF SPRAYING FRUIT TREES 27 



Cook (^, p. 261) claimed that bees are very susceptible to arsenicals 

 sjjrayed on trees, but he did not ascertain this experimentally. The 

 same author {3) experimented later with honej^bees and several other 

 insects. He confined them in cages and fed them mixtures composed 

 of 1 pound or less of London purple to 200 gallons of water or sirup. 

 Mixtures of 1 pound to 200 gallons were quickly fatal to honeybees. 



"Webster {13) sprayed a plum tree in full bloom with a mixture of 

 Paris green and water; he then covered the tree with sheeting and 

 mosquito netting and the ground with a canvas ; a few hours later a 

 hive of bees was placed inside the inclosure. The bees, instead of 

 working normally, flew wildly about inside the inclosure, probably 

 striking th'e foliage, flowers, sheeting, and netting; dead bees soon 

 began to accumulate on the canvas. When a few of them were 

 analyzed, arsenic was found; but its presence means nothing under 

 the circumstances. The same author {Uj.) performed experiments 

 on a larger scale by spraying two apple trees in full bloom and a 

 small orchard in which nearly all the petals had fallen. Several 

 bees caught visiting the trees sprayed in full bloom were killed in a 

 cyanide bottle, and parts of them were analyzed for arsenic; none 

 was found in the hind legs with pollen and contents of the thoraces, 

 but analyses of the contents of the abdomens, including the honey 

 stomachs, revealed arsenic. Other bees, taken from the same trees, 

 were killed, washed in dilute ammonia water, and analyzed, giving 

 distinct traces of the poison. A few days after spraying the small 

 orchard one of three colonies of bees near by suddenly became ex- 

 tinct and a second one greatly reduced in number of bees. From, the 

 totally depopulated colony Webster took dead bees, uncapped honey, 

 and dead larvse. When analyzed, the honey gave no evidence of 

 arsenic, but the dead larvse and the contents of the dead bees were 

 found to contain it. 



Woodworth (75, py;. Ill, H^)-, reporting the work done by Volck 

 at AVatsoiiville, in the Pajaro Valley, Calif., states that a hive of bees 

 was placed in the center of a 40-acre apple orchard, and then the 

 trees were sprayed when just coming into full bloom. Analyses 

 showed no arsenic in the new hone}^, but some in the pollen and dead 

 bees, that in the latter approaching a toxic dose. 



Holland (6') examined periodically in the laboratory many sam- 

 ples of dead bees ancL comb. A large percentage of the bees under 

 observation died within two or three days. No cause for their 

 deaths was known, except perhaps the spraying in the neighbor- 

 hood. A small quantity of arsenic was found in 12 of 23 samples 

 submitted for analysis. The detection of arsenic in the .stored pollen 

 was of special interest. Holland, using the approximate toxic 

 dose for the horse, ox, sheep, and fowl as a basis, would call the 

 toxic dose of arsenic for a honeybee about 0.005 milligram of 

 arsenious oxide (AsgO;,) or 0.006 milligram of ai'senic oxide 

 f As.O-), which is 10 or 12 times the actual lethal dose arrived at as 

 shown in the preceding pages. 



i-'ricc {Ifi) carried on experiments for two yeai'S in the field and 

 laboratory. In the fii'st year two apple ti'oes were caged with 

 (■h«'(;s('f'l(>th. One was sprayed with lime-sulphur and the other 

 diisterl with flowci's of siilfnr and arse.iiiite of lead, and a colony of 

 l)ees was put within each Jnclosiirc and liberated. In the second 



