REMEDIES AND PREVENTIVES. 61 
The very poisonous character of the potassium cyanide itself and of 
the hydrocyanic acid gas must be strongly impressed upon those who 
undertake to use this treatment for the first time. The cyanide must 
be kept where children and animals can not get at it: it must be kept 
in tightly closed vessels, and must be plainly labeled ••Poison." During 
the process of treatment every possible care must be taken to prevent 
human beings or domestic animals from inhaling the gas. 
EXPERIENCE WITH REMEDIES IN THE EAST. 
DIFFICULTIES MET WITH. 
Nearly fifty separate experiments were made with different was 
at varying strengths in the course of the work of the division with 
remedies for the San Jose scale in the East. Xo difficulty was experi- 
enced in effecting the destruction of the young in summer, and for a 
day or two after hatching any of the ordinary washes and strengths 
recommended for scale insects are perfectly satisfactory. The diffi- 
culty is, however, that the continuous emergence of the young from a 
single female covers a period of six weeks, and to effect the extermina- 
tion of the scales by the summer treatment necessitates applications 
practically every three days for nearly two months. This is ordinarily 
impracticable, and is much too expensive in time and material for 
general adoption. Eemedial work with washes against the San Jose 
scale is therefore limited to winter operations, when the scale is dor- 
mant and all the individuals are in practically the same condition and 
can be reached by one or two applications. 
The records of the experiments with winter washes conducted by the 
division at Eiverside are appended to this section as a matter of record 
and for purposes of comparison. 
VALUE OF THE DIFFERENT WINTEB WASHES. 
The following general conclusions will summarize the results obtained 
from the considerable series of experiments referred to: 
(1) The Oregon and California washes are practically valueless under 
the conditions obtaining in Maryland, even at twice the strength 
reported to be effective on the Pacific Slope. They are without action 
on the health or fruiting of the plant. 
(2) Lye washes are, in the first place, too expensive for use at the 
excessive strength required to accomplish any valuable results, and at 
this strength they also endanger the health of the plant. They do not 
seem to affect the blooming. 
(3) Pure kerosene applied to the entire plant kills the scales, but 
unfortunately also the plant, at least in the case of peach. 
(4) Kerosene and soap emulsion pure endangers the life of the plant. 
Diluted with one part of water it is not thoroughly effective, and this, 
with the trouble and expense of its preparation, rendi rs its use inad- 
visable. Diluted with one part of wafer, or m greater dilution, it does 
not seem to affect fruiting or the health o^ the tree. 
