14 



water. If the application is to be repeated, as it must be, 

 for the eurculio, to prove effective, or if it be used in June 

 or July, Paris green should be used, in the same proportion 

 as al)ove, or else we should only use one pound of London 

 purple to three hundred gallons of water. 



" Sixthly, If the arsenites are to be used on the peach, to 

 defend against the eurculio, Paris green only should be used, 

 and that not stronger than one pound to three hundred 

 gallons of water. 



" Seventhly, The injury done foliage is never immediately 

 apparent. It usually shows somewhat the second da}', but 

 the full injury is frequently not manifest till the fifth day, 

 and often not till the tenth." (Bulletin No. 53, Michigan 

 Agricultural Experiment Station, A. J. Cook.) 



As a result of experiments conducted by the Iowa Agri- 

 cultural Experiment Station and recorded in Bulletin No. 

 10, August, 1890, the following conclusions ' are drawn, 

 which the entomologist (Mr. C. P. Gillette) considers to 

 be well proven from the experiments he reports : — 



1. The oldest leaves are most susceptible to injury from 

 arsenical applications. They often turn yellow and drop 

 without showing the burnt spotted appearance. 



2. Dews, and probably direct sunlight, increase the 

 injuries done by the arsenites to foliage. 



3. Leaves kept perfectly dry can hardly be injured by 

 the arsenites, even when they are applied very abundantly. 



4. The only effect of a heavy rain or dashing shower 

 following an application of one of the arsenites is to lessen 

 the injury to foliage. 



5. When freshly mixed and applied, London purple is 

 most and white arsenic least injurious to foliage. 



6. White arsenic in solution should not be used upon 

 foliage without first adding lime, Bordeaux mixture or some 

 other substance to prevent its injurious effects upon foliage. 



7. White arsenic, if allowed to stand many days in water 

 before being applied, will do far greater harm to foliage 

 than if applied as soon as mixed. 



8. Lime added to London purple or Paris green in water 

 greatly lessens the injury that these poisons would otherwise 

 do to follag'e. 



