﻿UNITED STATES DEPARTMENT OF AGRICULTURE 



1^1 DEPARTMENT BULLETIN No. 1364 £^J 



Washington, D. C. ▼ 



May, 1926 



EFFECTS ON HONEYBEES OF SPRAYING FRUIT TREES WITH ARSENICALS 



By N. B. MclNDOo, Entomologist, Fruit Insect Investigations, and G. S. 

 Demtjth,' Apiciiltural Assistant, Bee Culture Investigations, Bureau of 

 Entomologij. 



CONTENTS 



Page 



Introduction . 1 



Effect on honeybees of spraying fruit ti^ees in full bloom 3 



Preliminary experiments, Winchester, Va.,. 1914 3 



More extended experiments, Winthrop, Me., 1914 4 



Effect on honeybees of spraying fruit trees at the customary time 10 



Experiments at Roswell, N. Mex., 1915 11 



Experiments at Benton Harbor, Mich., 1915 11 



Experiments at Winchester, Va., 1915 and 1916 12 



Experiments at Fennville, Mich., 1916 17 



Exi>eriments at Diiimmond, Md., 1917 19 



Interpretation of results 21 



Minimum amount of arsenic fatal to bees in confinement 23 



Methods 23 



Experiments and results 23 



Discussion of literature 26 



Summary 28 



Literature cited 32 



INTRODUCTION 



Ever since fruit trees have been sprayed with arsenicals beekeepers 

 liave been interested in the effect of this practice on the honeybee. 

 Years ago, when sprayed materials were often applied while the 

 trees were in full bloom, beekeepers became greatly excited and 

 widely distributed literature entitled " Don't Spray While in 

 Bloom." As a result of this agitation, according to Gates (7)^ one 

 Province in Canada and four States in the United States enacted 

 laws prohibiting the spraying of fruit trees in full bloom. As late 

 as December, 1920, there were laws to this effect in four States. 



The subject of poisoning bees is very large and of vital interest, 

 not only to beekeepers but to everyone who is interested directly 



1 Resigned June 30, 1923. The following men, who have also resiigned from the 

 Bureau of EntomolOKy, had change of the spraying in these experimenis at their re-- 

 srK-erive field stations: E. B. Bhikcslei' at VVin(;he»ter, Va., 1914, 1915, and 1916; F. L. 

 SImariton at Winthrop, Me., and at Benton Haibor, Mich., 1914 and 1915, rosi)ectlvely ; 

 and E. W. Ccycr at Uoswdl. X. .\lex., 1915. Tlie .lunior writer did part of the work at 

 Winchester, Va., 1915 and 1916, and at I'Vnnvillc, Midi., 1916, and th(^ Kcnioi- writer did 

 the remaining r>"rtion of thi- work here reported. Credit is due tlir Iii.secl icid-' and K'lnigi- 

 cide I«'it)<>ratory, Bni-cau of fhcmistry, for the clieniical work reported in this bulleliii. 



2 Reference (h made by number (italic) to " Mteratuie cited" p. 32. 



56797'— 26 1 



