﻿EFFECTS ON HONEYBEES OF SPEAYING FRUIT TREES H 



death rate of bees by daily weighing the colonies. Owing to un- 

 favorable weather in all three localities, the results obtained were 

 not conclusive, and the experiments were repeated in 1916 at Win- 

 chester and at Fennville, Mich,, a town in the fruit belt of the Great 

 Lakes, lying 6 miles from the eastern shore of Lake Michigan, by 

 both writers working together, using both methods. 



EXPERIMENTS AT ROSWELL, N. MEX., 1915 



In regions where the irregular blooming of apple trees causes a 

 long blooming period for an entire orchard, the trees to be sprayed 

 range in condition from those in full bloom to those from which all 

 the petals have fallen. Since it was desired to determine the damage 

 done to honeybees by spraying trees in such regions, three commer- 

 cial orchards, consisting of hundreds of acres of trees in an arid 

 region about Koswell, N. Mex., were selected for experimental pur- 

 poses. 



On April 8, 1915, two apiaries totaling 105 colonies lying near 

 these orchards were examined, and 10 dead-bee traps were installed. 

 Daily observations of the bees were made as usual. From this date 

 till April 23, when the first spray mixture was applied, bees in all 

 the colonies, except the two numbered 3 and 8, were dying ap- 

 parently at a normal rate. These two colonies suffered abnormal 

 losses and exhibited symptoms of arsenic poisoning; and when 10 

 samples from them, each of 75 dead bees, were examined, all were 

 found to contain arsenic, averaging 0.0003 milligram per bee. Eight 

 samples of old pollen, stored in these two hives and probably col- 

 lected from cover crops the preceding year, were also analyzed. 

 Each one contained arsenic, averaging 9 parts per million. 



On April 23, when on an average about 90 per cent of the petals 

 had fallen, the spraying was begun. During the afternoon of April 

 24 a hailstorm stripped the trees of practically all the remaining 

 petals, so that by April 26 every orchardist in the vicinity was be- 

 ginning to spray. The spray mixture consisted of 2 pounds of paste 

 lead arsenate to each 50 gallons of water, and was applied through 

 three leads of hose under pressure varying from 200 to 240 pounds. 

 Two 200-gallon power sprayers wore used in all the orchards. 



At regular intervals after the spraying was begun samples of dead 

 bees were taken from each of the 10 traps. Of 8 samples taken 

 from hives Nos. 3 and 8, which contained pollen stored in 1914, 7 

 contained arsenic, and of 16 samples from the other hives 15 con- 

 tained arsenic in very small quantities. On April 28, when these 

 experiments were discontinued, the 10 hives with traps were ap- 

 parently as strong as when the work was begun, and no symptoms of 

 arsenic poisoning were noticed except in the case of hives Nos. 3 

 and 8. 



EXPERIMENTS AT BENTON HARBOR, MICH., 1915 



Heavy rains and frccjiient hailstoi-ms in the region about Rosvvell, 

 N. Mex., marie conditions there abnormal for experimenting with 

 bees. As the blooming jjeriod in the fruit belt of the (h'cat Lakes 

 is comparatively long, it was decidtnl to i-epeat at Benton Harbor, 

 Mich., the experiments just described. On May 6, 1915, three small 

 orchards and two apiai'ies of 35 colonies were selected there for this 



