922 Report OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
sulphur washes applied in the fall may under certain conditions 
cause injuries such as sometimes attend the excessive use of 
these sprays‘in the spring. But it is believed to be advisable, when 
experience has shown that it is impossible to spray all of the 
trees in the spring, that fall spraying be employed for the treat- 
ment for the hardier varieties of fruits—as the increased vigor 
and usefulness of the trees arising from the control of the scale 
will more than compensate for probable losses in fruit yields. 
All of the washes tested proved equally effective in the destruc- 
tion of the scale. The addition of caustic soda or salt to a 
lime-sulphur wash cooked by fire or steam did not add to its effee- 
tiveness. While satisfactory in the present experiment later 
tests with the lime-sulphur-salt wash prepared without external 
heat showed that there may be considerable variation in the vari- 
ous preparations which may be largely avoided by using high 
grade lime and knack in the cooking operations. The washes 
that are well suited to the needs of average orchardists are the 
lime-sulphur wash boiled by fire or steam and the lime-sulphur- 
caustic soda wash, prepared without external heat. 
