REPORT OF STATE ENTOMOLOGIST 141 



two work in hearty cooperation for the general good of the State. 



Besides studying the life histories and gathering the necessary 

 information regarding these classes of insects, it is considered the 

 duty of the State Entomologist to experiment with insecticides and 

 acquire information regarding natural agencies which tend to des- 

 troy injurious species. 



PRICES OF INSECTICIDES IN MONTANA. 



During the past two years, while traveling about the State, we 

 have made inqu ; ~ies at many points regarding the kinds and amounts 

 of insecticides used, and some observations of considerable import- 

 ance have been made. For many years Paris green has been the 

 standard remedy for the Colorado potato beetle and the country uses 

 annually many thousands of pounds of this insecticide for their de- 

 struction. The Gypsy Motth Commission of the State of Massa- 

 chusetts, in performing its duties in the control of the notorious 

 gypsy moth, found that the Paris green was not effective as a 

 remedy and set about discovering a more suitable arsenical for the 

 purpose. After much experimenting they found that arsenate of lead 

 had marked advantages over Paris green for their work, its three 

 principal advantages being the following: 



1. It can be applied in almost any strength without injuring 

 even the most delicate foliage. 



2. It adheres to the foliage better than Paris green and is not 

 easily washed off by rainstorms. 



3. It is white in color and is easily detected on the foliage of 

 plants. 



These advantages have been widely advertised and many firms 

 have begun the manufacture of arsenate of lead. Their products 

 have been sent all over the country and are generally all that is 

 claimed for them, when not adulterated or misbranded, but unfortun- 

 ately the price, in many instances, has been made such that arsenate 

 of lead is forced to compete with Paris green, pound for pound. In 

 killing power Paris green is from three to four times as strong as 

 arsenate of lead and the wholesale price of the latter is only about a 

 third or fourth as much as that of the former. 



In spite of these facts, however, many merchants have been 

 selling lead arsenates at about the same price as Paris green and have 



