54 BULLETIN 1201, U. S. DEPARTMENT OF AGRICULTURE. 



Of the 260 species of plants catalogued, 94 were found by the 

 writers and others to have little or no effect as insecticides, and 109 

 other species are recorded by other writers as used for insecticides, 

 but without citation of experimental evidence. 



CONCLUSIONS. 



Of the 260 species of plants catalogued, only about 5 per cent 

 furnish material for efficient insecticides, and of these only about 

 half may be regarded as satisfactorily efficient. The latter include 

 three species of Chrysanthemum (cinerarias folium, coccineum, and 

 marschaZlii) , used for making pyrethrum or insect powder; two 

 species of Derris (elliptica and uligmosa) ; and a Peruvian plant 

 known locally as " cube." The extracts of these, combined with soap, 

 proved to be promising contact insecticides and compete favorably 

 with nicotine sulphate in efficiency and probably in cost. 



Eelative to the other species catalogued, most of them are not 

 worth further consideration. It does not seem at all probable that 

 satisfactory insecticides can be obtained from the commoner weeds or 

 flowers or from plants known to be only slightly poisonous to man 

 or other animals; but with regard to the poisonous plants, particu- 

 larly the fish-poisons, found in the Tropics or subtropics the chances 

 to obtain other efficient insecticidal material are very promising. 



LITERATURE CITED. 



(1) Abbott, W. S. 



1920. Results of experiments with miscellaneous substances against 

 chicken lice and the dog flea. U. S. Dept. Agr. Bui. 888, 15 p. 



(2) Andre, E. 



1904. Nouveaux procedes de destruction de l'oidium et du puceron 

 lanigiere. In Rev. Hort., 76 annee, t. 4, Paris, p. 83-84. 



(3) Anonymous. 



1863. Anthemis cotula. In Pharm. Ztschr. fur Russland, jahrg. 1, no. 

 23, p. 578. 

 (4) 



(5) 



1875. Ersatz des persischen Insektenpulvers. In Ztschr. Allg. Osterr. 

 Apoth. Ver., 13 jahrg., no. 21, p. 346. 



(6) 

 (7) 



(8) 



1886. Ricinus communis as an insect powder. In Chemist and Druggist, 

 v. 29, Sept., p. 410. 



1892. Insektenpulver. In Pharm. Ztg.. 37 jahrg., no. 103, Dez., p. 798. 



1901. Catalogue of collections of pests and insecticides (Com. Agr. 

 Parasit. Secy. Pub. Prom. Mexico, 1901, p. 6). In Exp. Sta. 

 Record, v. 13, 1901 and 1902, p. 474. 



1917. Infusion of broom tops as a larvicide. In Pharm. Jour, and 

 Pharmacist, v. 98 (4th ser., v. 44), no. 2783, p. 139. 

 (9) Back, E. A., and Rabak, Fkank. 



1922. Red cedar chests as protectors against moth damage. U. S. Dept. 

 Agr. Bui. 1051, 14 p. 



(10) Bekgey, D. H. 



1912. The principles of hygiene. Philadelphia, p. 399. 



(11) Bishop, Wm. D. 



1S59. Government experimental and propagating garden. In Rpt. Comm. 

 of Patents, Agr., p. 13, Washington, 1860. 



(12) Bohmee, K. 



1895. TJeber Chrysanthemum corymbosum. In Pharm. Ztg., jahrg. 40, 

 no. 64, Aug., p. 523. 



