INSECTICIDES AND FUNGICIDES. 



without inconvenience, and will you, purchase through some farmer friend, who is 

 not known to be in close relations with entomologists or chemists, a series of pound 

 samples of the insecticides on sale in your vicinity and send them to this office or to 

 the Chemist, with memorandum bill of expense ? Samples may be sent under the 

 inclosed franks, and if you wish more franks I will forward them to you. Accom- 

 panying each sample should be a statement of the date and place of purchase, price 

 paid, and the name of the manufacturer. 



All assistance will be gladly and publicly acknowledged, and I trust that you will 

 be willing to assist in this interesting work. Of course, similar work has been done 

 by some of the experiment stations, but it seems desirable that it should be done for 

 the whole country. The idea originated in the Division of Chemistry, and this 

 Division is simply collaborating so far as possible. 



Most truly yours, L. O. HOWARD, Entomologist. 



Of the samples received, amounting to about 300, all those were 

 rejected which did not give fairly complete data as to the price paid, 

 name of manufacturer, and name of retailer. Again, many duplicate 

 samples were received. In case such samples were in sealed packages 

 and came from the same manufacturer only one was analyzed, but in 

 case the samples came from the same manufacturer but were not sealed 

 as many as were received were analyzed, since in the latter case altera- 

 tion of the sample b}^ the jobber or retailer was possible. 



After sifting down the samples in this manner, 156 were finally 

 chosen for analysis. It is thought that these samples fairly represent 

 the present state of the market in the United States. 



It is not the intention in this work to go into the various applica- 

 tions of these compounds to the treatment of insect pests and plant 

 diseases, as this is a field which belongs more directly to the entomol- 

 ogist or plant pathologist. We simpty desire to give the chemical 

 composition of such preparations, and thus show the public what they 

 are buying. Along with this are given the methods of analysis 

 employed (many of which were devised especially for this work), and 

 some discussion as to whether such compounds are injurious to plants 

 or will serve the purposes for which they are intended. 



The insecticides and fungicides are arranged in groups as far as pos- 

 sible, and they will be considered in the following order: (1) Paris 

 greens; (2) London purples; (3) insecticides and fungicides, other 

 than paris greens and London purples, that contain arsenic, copper 

 or both; (4) soaps; (5) hellebores; (6) pyrethrums; (7) mixtures con- 

 taining borax; (8) mixtures containing free phosphorus; (9) tobacco 

 extracts; (10) miscellaneous solid insecticides and fungicides; (11) mis- 

 cellaneous liquid insecticides and fungicides. 



SOURCES AND DESCRIPTIONS OF SAMPLES. 



Before proceeding with the discussion of the groups, Table I, on the 

 next page, is introduced to show the source and description of all 

 samples examined. 



