SPRAYING PEACHES WITH ARSENICALS. 203 
Gillette, Galloway, Woods, Fairchild, Sturgis, Baine, and Iledrick. 
It was found that the addition of lime to the Paris green or London 
purple spray greatly reduced its causticity, and the use of Paris 
green in this way was recommended for peach by Haywood, who says: 
In spraying peach trees, none of the Paris greens bought upon the market should 
be used without the addition of lime. 
For peach trees sprayed with the use of lime, the amount of soluble arsenic oxid 
allowable lies between 3 and 6 per cent, a fair average being Ah per cent. 1 
Nevertheless, even with the use of lime two or three applications 
of a Paris-green spray very generally resulted in defoliation of the 
trees, and in recommendations for the use of arsenicals on peaches 
this risk was very generally pointed out and understood by the 
majority of peach growers. 
The development of arsenate of lead, a stable compound con- 
taining practically no free arsenic, it was thought would furnish an 
arsenical which might be used without injury on peaches. Experi- 
ments to determine its usefulness were at once begun by entomolo- 
gists, and while it was noticeably less injurious than Paris green or 
London purple, yet in the South especially several applications, as 
deemed necessary for the control of the insect, caused a considerable 
amount of foliage to fall and often resulted in burning of the fruit. 
Arsenate of lead, however, was generally recommended for peach 
spraying by the manufacturers and also with caution by many 
entomologists and horticulturists. Not a few orchardists who tried 
the poison experienced disastrous results, whereas comparatively 
little injury was noted by others, who preferred to take the risk of 
foliage and fruit injury in preference to suffering the ravages of the 
curculio. 
In a word, opinion was divided as to the advisability of spraying 
peaches with arsenate of lead, with perhaps on the whole a distin< ( 
prejudice against it. 
In the course of the present curculio studies particular attention 
has been directed to the question of arsenical injury to peaches. 
During 1906 green arsenoid, Paris green, and arsenate of lead (both 
commercial and homemade) were tried on peaches according to a 
uniform plan of treatment in the Southern. Middle, and Northern 
States, in order to secure if possible comparative data from these 
regions. In all localities the green arsenoid and Paris green (.'> 
applications each of 4 ounces to 50 gallons of lime water) proved 
injurious, defoliating trees almost completely. In northwestern 
Pennsylvania neither the commercial nor the homemade lead arsenate 
(3 applications at the rate each of 2 pounds to 50 gallons of lime 
water) caused noticeable injury. In Virginia the homemade lead 
I Bui. 82, Bur. Cheiu., U. S. Dept. Agr., p. 33, l l J04. 
