INSECTICIDE AND FUNGICIDE BOARD. 429 



of the Raw Materials Division, Council of National Defense, in 

 arranging for the substitution of vinegar for acetic acid in the 

 manufacture of Paris green, since all acetic acid is needed by the 

 Government in the development of its aeroplane program. The 

 board's representative has been able to supply certain needed chemi- 

 cal and practical advice at various conferences between the Wood 

 Chemical Section of the Raw Materials Division and manufacturers 

 of Paris green. As a result of these conferences a decision was 

 reached that no more acetic acid could be supplied for the manufac- 

 ture of Paris green after July 1, 1918. It has been arranged, however, 

 that an ample supply of vinegar will be produced for use in manu- 

 facturing Paris green. 



Plant pathologists of the board working in cooperation with the 

 Bureau of Plant Industry have continued investigations relative to 

 the practical value of several types of fungicides concerning which 

 reliable or conclusive data have heretofore been lacking. Additional 

 results have been obtained relative to the efficiency of dusting mix- 

 tures for use in controlling various plant diseases. Considerable in- 

 formation of value to the board in connection with the enforcement 

 of the act has been obtained by a study of the relative values of the 

 various types of sulphur compounds, such as the sodium polysulphids 

 and calcium polysulphids. The compilation of the results of this 

 work with a view tt) publication is now under way. Valuable data 

 were also obtained relative to the effect of combining different types 

 of arsenicals, such as lead arsenate and calcium arsenate, on the fun- 

 gicidal value and injurious properties of these sulphur compounds. 

 An investigation comparing results with Bordeaux mixtures contain- 

 ing various amounts of copper has given important data concerning 

 the amount of copper necessary in commercial Bordeaux mixtures to 

 insure satisfactory control of certain plant diseases. 



In collaboration with the Bureau of Plant Industry, material was 

 prepared for Farmers' Bulletin 994, entitled " Commercial Bordeaux 

 Mixtures — How to Calculate Their Values." The object of this 

 bulletin is to aid the users of commercial Bordeaux mixtures to cal- 

 culate from the composition as stated on the label, in terms of the 

 formula by which they commonly express the strength of home-made 

 mixtures, the amount of equivalent copper sulphate such commercial 

 mixtures would contain when diluted for use as directed, and to give 

 methods whereby the dilution recommended may be so changed as to 

 produce a mixture in each case equal to the Bordeaux formula re- 

 quired for the purpose in question. The bulletin also discusses 

 briefly the physical properties of Bordeaux mixtures and suggests 

 methods of determining readily good and poor physical properties. 



During the year the entomologists of the board, working in co- 

 operation with the Bureau of Entomology, have completed the work 

 relative to the action of a large number of chemicals on bedbugs, 

 cockroaches, clothes moths, and carpet beetles, and publication has 

 been made as a professional paper under the title, " Results of Ex- 

 periments with Miscellaneous Substances Against Bedbugs, Cock- 

 roaches, Clothes Moths, and Carpet Beetles " (United States Depart- 

 ment of Agriculture, Bulletin 707). This paper, the first of several 

 to be published on the results of tests with various substances against 

 many different insects, is of value to manufacturers, in that it gives 



