CONTENTS. Insecticides and fungicides, other than Paris Green and London Purple, that contain arsenic or copper, or both, as their active constituent..... 42 Mixtures containing borax THE CHEMICAL COMPOSITION OF INSECTICIDES AND FUNGICIDES. INTRODUCTION. Since the data on the chemical composition of insecticides and fungicides is extremely meager and no systematic work has been done, to the knowledge of the writer, in this direction by either State experiment stations, private individuals, or the National Government, it was considered that it would be interesting as well as instructive to make a chemical study of this class of compounds. It is true that several States have laws relating to the composition and sale of Paris Green, notably, Texas, California, Louisiana, and New York, and the last of these States publishes each year the composition of insecticides other than Paris Green, but such work as is done, excluding Paris Green, is, up to the present date, very meager. Even in those States having laws governing the composition of Paris Green, California is the only one, so far as the writer is informed, which requires that the free arsenious oxid shall be below a certain fixed percentage. In pursuance of the study of the subject the chief of the Bureau of Chemistry in the spring of 1900 requested the chief of the Division of Entomology to collect samples of as many insecticides and fungicides as possible throughout the United States. This branch of the work was placed in the hands of Mr. R. S. Clifton, of the Division of Entomology. The following circular letter was sent to all State experiment stations and to several of the special agents of the Department in different localities: U.S. DEPARTMENT OF AGRICUlture, DIVISION OF ENTOMOLOGY, Washington, D. C., March 28, 1900. DEAR SIR: The Division of Chemistry of this Department is about to undertake, in collaboration with this Division, an extended investigation of the insecticides which are being sold on the open market in al! parts of the country. With your experience you can readily understand that if the samples to be analyzed were purchased direct by this Department from the manufacturers we would have no guaranty that they would not be doctored, and it seems necessary therefore to avoid giving the information that they are purchased for chemical analysis. I have thought that the best way we can secure them is to ask for your assistance, together with that of other members of the American Association of Economic Entomologists. Can you, 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. Accompanying 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 alteration of the sample by 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 applications of these compounds to the treatment of insect pests and plant diseases, as this is a field which belongs more directly to the entomologist or plant pathologist. We simply 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 possible, 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 containing borax: (8) mixtures containing free phosphorus; (9) tobacco extracts; (10) miscellaneous solid insecticides and fungicides; (11) miscellaneous 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. |