1912.] PUBLIC DOCUMENT — No. 31. 179 



commodity of southwestern Asia for a long time, but appears to 

 have been overlooked by early European and American agricul- 

 turists, being introduced into Erance about 1850. The efficacy 

 of kerosene, fish and whale oils, and turpentine was acknowl- 

 edged comparatively early, though they were seldom used on 

 account of the liability to injure the plant. The fact that such 

 substances must be miscible with water to be applied safely was 

 recognized long prior to an understanding of how it could be 

 accomplished. An emulsion ' of kerosene with soap and water 

 was apparently not used until 1870. Soap and water has prob- 

 ably been more extensively employed in the past than any other 

 substance, both for its effect and as a vehicle. Whale oil soap - 

 was recommended in 1842. Lime and sulfur were almost inva- 

 riably mentioned by early writers on insecticides. They jointly 

 appeared in a number of mixtures, and where heat was em- 

 ]iloyed in their preparation ^ partial combination, at least, must 

 have taken place. This product was a forerunner of the lime- 

 sulfur compounds which have since proved so valuable in check- 

 ing the San Jose and other scales. 



While the above summary may fail to convey a clear under- 

 standing of the subject, it will serve to show that practically no 

 active " food " poison had been used as an insecticide previous 

 to 1860. 



The advent of the potato beetle "* in ISTebraska in 1859 and its 

 rapid spread eastward created a demand for a more powerful 

 insecticide than those commonly employed. In a measure this 

 was true also of the imported currant worm which appeared in 

 the eastern States about 1858. The poisonous nature of arsenic 

 was well understood, and its salts would naturally be expected 

 to possess a like property. Paris (Schweinfurt) green had 

 long been known as a pigment under various trade names and 

 Avas first applied ^ as an insecticide for the potato beetle about 

 1868, from which time its use was gradually extended to the 

 cotton worm, cankerworm, codling moth and other insects. Sub- 

 sequently a number of other arsenicals were recommended, of 



' Geo. Cruickshank in Gardener's Monthly, 1875, p. 45. 



2 David Haggerston in History of Mass. Hort. Soc, 1829-78, p. 256. 



3 Kenrick, loc. cil., p. XXXVI., and for grape mildew, p. 328 (1833). 



4 C. V. Riley, Potato Pests, pp. 12-24 (1876). 



6 Geo. Liddle, Sr., in Amer. Ent. 1, p. 219 (1869). 



