INSECTICIDE AND FUNGICIDE BOAJJD. 1099 



PARIS GREEN. 



Among the very first questions which arose in connection with 

 the enforcement of the insecticide act was that of estabhshing a fair 

 method by which the amount of arsenic in water-soluble forms in 

 Q.nj green might be determined, in view of the provision of the law 

 which limits that ingredient to the equivalent of not more than 3^ 

 per cent of arsenious oxide. In comphance with the request of 

 many manufacturers a public hearing was held in order that they 

 might be given an opportunity to present their views. The meeting 

 was largely attended, and all of the leading manufacturers in the 

 United States were represented. Following this, laboratory experi- 

 ments were made witn a large number of greens to determine the 

 rapidity of "breaking up" for different periods and under variable 

 conditions. Spraying tests were also made. The results, however, 

 were not considered sufficiently conclusive. Further investigations 

 are progressmg with a large variety of greens which are undergoing 

 exhaustive laboratory tests and are the subjects of experiment on a 

 large scale in the field. 



TOBACCO POWDERS. 



The manufacturing interests engaged in the production of tobacco 

 dust or powder for fumigation or other insccticidal purposes have 

 been uncertain as to the proper method of declaring tne inert ingre- 

 dients, as required by the law. This question has received a great 

 deal of attention during the past year. An expert under direction of 

 the board has visited 53 firms representing all phases of the tobacco 

 industry as carried on in 15 different citieS. In addition to this 

 investigation of the tobacco industry, extensive experiments have 

 been carried out ^vith tobacco powders on various insects. A final 

 conclusion as to the proper method of labeling tobacco powders 

 under the insecticide act has not yet been reached, but it is hoped 

 that a decision will be issued at an early date. 



BORDEAUX MIXTURE. 



By reason of the various requests from manufacturers for informa- 

 tion relative to what are to be considered the active and what the 

 inert ingredients of Bordeaux mixture a laboratory investigation was 

 carried on to determine the effect of the constituents of Bordeaux 

 mixture on fungi. An extended investigation of all chemical litera- 

 ture relative to the composition of Bordeaux mixture and of the 

 hterature relative to spraying with Bordeaux mixture was also made. 

 As a result of this work it was determined that only the copper com- 

 pounds possessed fungicidal value, and that any or all of five or six 

 comphcated copper compounds might be present in a Bordeaux mix- 

 ture, according to its method of preparation. It was further decided 

 that not only was it impossible to determine just which of these 

 copper compounds were present in a given Bordeaux mixture, but it 

 was not necessary to do so inasmuch as it was only the copper from 

 these compounds, which being slowly rendered soluble by weather- 

 ing, possessed fungicidal qualities. As a result of this investigation 

 Insecticide Decision No. was published. 



