New York AGRICULTURAL EXPERIMENT STATION. AEM 
“ Boil until the arsenic is all dissolved, which will take about 
fifteen minutes. Replace the water lost in boiling, as otherwise 
some of the material will crystalize upon cooling. This makes a 
stock solution of arsenite of soda, which may be placed in tightly 
stoppered jugs or bottles and kept on hand for use as needed. 
The vessels used in making and storing the solution should be 
plainly labeled ‘Poison’ and never used for any other purpose. 
“Two quarts of this stock solution are equivalent to 1 pound 
of paris green. This is the quantity which should be used on an 
acre of potatoes. At the rate of 1 to 2 quarts in 50 gallons 
it may be used with bordeaux mixture without danger of injury 
to the foliage, but it must not be used alone. Even with lime 
water it can not be safely used at a greater strength than 1 
quart of stock solution with 4 pounds of lime in 50 gallons of 
water.” ) 
IS IT SAFE TO PLANT WHERE POTATOES BLIGHTED THE PREVIOUS 
SEASON ? 
-“The above question is often asked. The answer depends on 
the nature of the blight. If the blight in question is late blight, 
the fact the plants blighted last year has no bearing on this year’s 
crop so far as planting on the same land is concerned. The fun- 
gus of late blight does not live over winter in the soil.®° 
“If the blight is due to the dry-rot fungus (Fusarium oxy- 
sporum), or to the bacterial wilt organism (Baccillus solancea- 
rum), the land should not, at once, be used for potatoes, since 
these diseases are harbored from year to year in the soil. 
“Yor early blight a satisfactory answer cannot be given. The 
facts are not known.” 
BLIGHT-PROOF VARIETIES. 
“ While some varieties suffer more than others from both early 
and late blight, there are none entirely blight-proof and probably 
none sufficiently resistant to make spraying unnecessary. Re- 
% Director Woods of the Maine Station has recently advanced the opinion 
(Me. Exp. Sta. Bul. 112: 5) that, “ Potatoes may be infected directly in the 
field from spores introduced in the manure, or from rotten potatoes spread 
upon or left in the land the preceding year.” We hold that observed facts 
do not warrant this corclusion. In the case on which Woods bases his 
opinion (Loc. cit. pp. 1-2) the rotting of the tubers was probably due to 
infection which occurred at the time of digging when the tubers were brought 
into contact with live Phytophthora blight spores on the green tops. 
