JOIMALOFAGKICDITIKALISEARCH 



Vol. X Washington, D. C, September 3, 1917 No. 10 



QUASSIA EXTRACT AS A CONTACT INSECTICIDE 



By N; E. McIndoo, Insect Physiologist, Deciduous Fruit Insect Investigations, Bureau 

 of Entomology, and A. F. SiEVERS, Chemical Biologist, Drug-Plant and Poisonous- 

 Plant Investigations, Bureau of Plant Industry, United States Department of 

 Agriculture 



INTRODUCTION 



According to the literature, it appears that the extract from the 

 Jamaica quassia wood (Picrasma excelsa Swz.) when properly extracted 

 and applied is an efficient and satisfactory insecticide for the hop aphis 

 (Phorodon htimuli Schr.); but, owing to the fact that the active con- 

 stituent of quassia wood is not toxic in the usual sense, authorities on 

 insecticides are not yet agreed concerning the efficiency of quassia extract. 

 Since this extract has never been used extensively upon other species of 

 aphids, it is desirable to know whether or not it may be employed as a 

 general insecticide for all aphids. Before being able to determine this 

 point for aphids in general, it is first necessary to make a careful study 

 of the economic methods of the extraction of quassia wood in order to 

 determine what process assures the most thorough extraction of such con- 

 stituents as are found by means of tests on aphids to be the toxic princi- 

 ples. It is further necessary to observe the physiological effects of this 

 poisonous substance upon aphids. In this investigation, therefore, two 

 chief objects have been kept in view: (i) To determine the efficiency of 

 various extracts of quassia wood, and (2) to study the pharmacological 

 effects of these extracts upon insects. 



HISTORICAL REVIEW 

 1. — LITERATURE DEALING WITH QUASSIA AND OUASSIIN 



According to the Ninth Decennial Revision of the United States 

 Pharmacopoeia, official quassia is derived from either Picrasma excelsa 

 (Swz.) Planch, (family Simarubaceae) , known commercially as Jamaica 

 quassia, or from Quassia amara L. (family Simarubaceae), known com- 

 mercially as Surinam quassia. According to the literature, there are a 

 number of other plants which furnish wood with similar characteristics, 

 whose active constituent is identical with, or similar to, quassiin, the 

 bitter principle and main constituent of official quassia. These plants 



Journal of Agricultural Research, Vol. X, No. lo 



Washington, D. C. Sept. 3, 191 7 



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