TOXICITY OF VOLATILE ORGANIC COMPOUNDS tO 



INSECT EGGS^ 



By William Moore, Head of Section of Research in Economic Zoology, and Samuel A. 

 Graham, Assistant in Entomology, Minnesota Agricultural Experiment Station 



INTRODUCTION 



A general sur\"ey of the literature has failed to reveal any extensive 

 study of the toxicity of different materials to insect eggs. Certain spray 

 solutions have been studied, but they have been considered individually 

 and not in comparison with other related compounds. 



Cooley (j)^, working with the oyster-shell scale {Lepidosaphes tdmi L.) 

 has shown that linseed oil, cottonseed oil, and lime-sulphur were effective. 

 In the cases of the oils some of the eggs were killed, while other eggs 

 hatched, but the young insects died during or shortly after emergence. 

 Lime-sulphur failed to kill the eggs, but the young were killed very soon 

 after hatching. Pure kerosene apparently had no effect on the eggs. 



Gillette (2), working with aphid eggs of different species, has shown 

 that eggs treated with kerosene emulsion containing less than 25 per 

 cent of keresene were unaffected by the spray. Scalecide, Thompson's 

 Soluble Oil, lime-sulphur, and different soaps had little effect unless used 

 in very large doses. Tobacco extracts containing nicotine or nicotine 

 sulphate were found to be very effective. 



Safro (9), in the study of lime-sulphur as an ovicide for the codling 

 moth (Carpocaspa pomenella L.), shows that this material is only effective 

 to eggs in which the embryo is almost fully developed. 



Woodworth (lo) has studied the toxicity of hydrocyanic-acid gas 

 to the eggs of scale insects, but does not consider the factor of age. 



Recently particular attention has been given to the study of the 

 toxicity of volatile organic compounds to the eggs of lice (Pedictdus 

 capitis and P. corporis, and Phthiris pubis). Kerosene has been used 

 against head lice and their eggs for many years, but in the recent work 

 many other materials have been recommended. 



Postnikov (7) recommends amyl alcohol, ethyl alcohol, benzene, 

 chloroform, carbon tetrachlorid, methane, and birch tar for the destruc- 

 tion of head lice and their eggs. Gasoline has been used for the destruc- 

 tion of the eggs of the clothes louse, and Klinloch (4) claims that im- 

 mersion in this material for one minute will kill, while exposure to its 

 vapor is fatal in one-half hour. He considers that benzene, toluene, 



1 Published, with the approval of the Director, as Paper 88 of the Journal Series of the Minnesota Agri- 

 cultural Experiment Station. 

 * Reference is made by number (italic) to "Literature cited," p. 586-587. 



Journal of Agrictiltural Research, Vol. XII, No. 9 



Washington, D. C. Mar. 4, 1918 



™^ (579) ^^^ ^°' ^^""i- — 24 



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