208 Report or THE BOTANICAL DEPARTMENT OF THE 
potato blight and thereby increased the yield at the rate of 46 
bushels per acre. However, it should be noted that late blight 
was exceedingly virulent at Geneva in 1904 and that the quantity 
of paris green used (about 12 pounds per acre) was larger than 
farmers usually apply. It should be noted, also, that under 
parallel conditions 5 sprayings with bordeaux mixture increased 
the yield 14214 bushels per acre. Thus it appears that paris green 
has at least one-third the fungicidal value of bordeaux mixture. 
Jones?! has called attention to the fact that paris green injury 
is especially liable to occur where the epidermis of the potato leaf 
has been broken, as for example, around the punctures made by 
flea beetles. In this experiment there were no flea beetles, but 
Colorado potato beetles mutilated the leaves on some of the plants 
without any paris green injury resulting therefrom. 
The failure of paris green to produce injury in this experiment 
cannot be attributed to unfavorable weather conditions. 
Throughout the season there was an abundance of rain which is 
generally regarded as favorable to paris green injury. 
As previously stated, the chemical composition of paris green 
is variable. Some samples contain a larger percentage of soluble 
arsenic compounds than others and consequently some are more 
liable to injure foliage than are others. In some states this is 
regulated by law. In New York legal paris green must not con- 
tain move than 314 per ct. of soluble arsenic compounds. Analy- 
ses made at this Station show that the great majority of the paris 
green offered for sale in New York complies with the law.?2 As 
regards the content of soluble arsenic the paris green used in this 
experiment is fairly representative of the paris green found on 
the market. 
The conclusion is that partis green is not injurious to potato 
foliage when properly applied; that is, in moderate amount (one 
to two pounds per acre) with lime water or bordeaux mixture 
evenly distributed over the foliage. 
THE EXPERIMENT WITH ARSENITE OF LIME. 
PLAN AND METHODS. 
This experiment included 20 rows 290.4 feet long and three 
feet apart, each row having an area of one-fiftieth acre. The 
1 Jones, L. R. Vt. Exp. Sta. Bul. 49: 97. 
See Bulletins 204 and 222 of this Station. 
