Spraying with Paris Green. 61 



In after years, several other patents were granted upon various 

 mixtures in which this poison held a prominent position. 1 The 

 arsenite was most generally applied, however, by being mixed 

 with flour, plaster, or ashes, the proportions varying from two 

 to ten or twelve parts of the diluent to one of the poison. 

 The proportion of poison was greatly reduced in later years, 

 only one part to twenty-five or thirty being used. 



Applications of Paris green, when mixed with water, do not 

 appear to have been commonly made during the first few years 

 following the introduction of the poison. The difficulty of 

 transporting the water appears to have been one of the main 

 objections to this method ; and another, perhaps an even more 

 serious one, was the imperfect distribution which resulted from 

 sprinkling the plants with the aid of only very unsatisfactory 

 appliances, watering-cans or brooms being at first used for this 

 purpose. It is only since the introduction of improved ma- 

 chinery that the poison has been generally applied in this 

 manner. 



The success attending the use of Paris green in the destruc- 

 tion of the potato-beetle soon suggested its application to plants 

 that suffered from similar insect pests. In 1872 Riley sug- 

 gested the treatment of cotton plants with Paris green for 

 the destruction of the cotton worm. 2 It was advised to use 

 from one-half to one pound of the poison in forty gallons of 

 water, this being considered as sufficient for a single treatment 

 of an acre. The poison is still extensively used, although the 

 proportions of the water and the arsenite have varied. 



Le Baron, in 1872, made a suggestion which was followed 

 by consequences vastly more important than were probably 

 dreamed of by its originator. The spring canker-worm of the 

 apple was doing much damage in the West, and in spite of the 

 many devices invented for its capture or destruction, the pest 

 continued to spread, and serious losses were inflicted. The 

 recommendations made by Le Baron, 3 at that time state entomol- 

 ogist of Illinois, were for the growers to place their main reli- 

 ance upon measures which prevented the insect from gaining 

 a foothold in the trees. In case such precautions should be 



i Riley, U. S. Ent. Com. 1880, Bull. 3, 5T. 



* Ibid. 56. 



8 Second Ann. Kept, on the Noxious Insects of the State of Illinois, 18T2, 116. 



