New YorK AGRICULTURAL EXPERIMENT STATION. 307 
of water, to determine their value as dips, no injuries were appar- 
ent to any of the trees, even when the roots were immersed in the 
liquids. These proved not only safer but the stronger prepara- 
tions were also much more effective on the scales than the sul- 
phur wash. Kerosene emulsion, containing either 15 or 20 per ct. 
of oil, and miscible oil, diluted with either 10 or 15 parts of water, 
were generally very efficient. With the exception of.a few trees 
on which there was a little breeding, the stock was cleaned of 
the scales. Fumigation with hydrocyanic acid gas at the rate of 
0.3 gram of cyanide per cubic foot caused no appreciable harm 
to the trees and completely destroyed the scales, 
DISCUSSION OF RESULTS AND CONCLUSIONS. 
The purpose of these experiments was to determine the merits 
of the standard lime-sulphur wash as a dip for the treatment of 
nursery trees. In this endeavor, efforts were principally directed 
to determine the safeness of dipping trees in this mixture and the 
probable effects of this operation in field practice accomplishing 
the real object of the work, 1. e., to clean the stock of San José 
scale. The experiments have yielded data bearing on both of these 
points, which show plainly that the immersion of the roots of 
fruit trees in a sulphur wash may be accompanied with serious in- 
juries to the stock, and that this treatment does not entirely de- 
stroy the scales. In view of these limitations, it is believed that 
this method of disinfecting nursery trees is a doubtful practice for 
both nurserymen and fruit-growers, neither of whom can afford 
to take chances on the reliability of their purchases and shipments. 
In the light of these experiments, uncertain and disappointing re- 
sults could hardly fail to follow the employment of this kind of 
treatment for nursery stock. Until more knowledge is obtained of 
the strength of the sulphur wash that will effectively control the 
scale, dipping of the tops of trees in this mixture for purposes 
of disinfection should be regarded as wholly experimental. As 
immersion of the tops of the trees in the standard sulphur wash 
at temperatures of from 60° to 120° F. for short time periods 1s 
unattended with important injuries, it is possible that stronger prepa- 
rations of the sulphur wash can be employed for the treatment of 
stock, excluding the roots, which will give efficient results on the 
scales and will not prove harmful to the plants. 
The results obtained with the oil emulsions and miscible oils in- 
dicate that they are more efficient for dipping purposes than is the 
