56 THE SAN JOSE SCALE. 
REMEDIES AND PREVENTIVES. 
CONFLICTING RESULTS BETWEEN WEST AND EAST. 
Experience with different methods of destroying this scale, in both 
winter and summer treatments, early demonstrated that the methods 
reported as effective in California and other Pacific States, are com- 
paratively valueless in the East. This is particularly true of the 
winter washes. This condition of affairs, which by the way was totally 
unexpected, may find a partial explanation in a variation in the habits 
of the insect. In California, especially in the southern part of the State, 
the development of the successive generations of the scale is not so com- 
pletely interrupted by the winter season, and the scales, not so gener- 
ally assuming the dormant condition and perhaps not developing so 
dense a scale covering, seem to be less resistant to washes, and to be 
amenable to strengths which in the East have been nearly without 
effect. Against this explanation it may be urged that a strong, vigor- 
ous growing scale will naturally be more resistant to the action of washes 
than a more or less completely dormant one whose vitality is reduced 
by long lack of food. Certain of our experiments, in fact, seem to sug- 
gest that this may be the case, although, on the whole, we are inclined 
to doubt it. A better explanation, therefore, probably lies in the fact 
that, in the use of winter washes, in which difference in results is 
particularly noticeable, these applications are made in Calfornia some- 
time before the rainy season begins, and hence have their full effect on 
the trees and the scales before they are washed off by rains. 
In other words, the differences in precipitation and moisture between 
the two sections may be more influential in bringing about the failure 
of California winter washes in the East than are differences in 
temperature. 
This noticeable difference in the effect of California washes on scales 
in the East was first discovered sometime ago by Mr. Marlatt in work 
upon other scale insects affecting fruit, notably in the case of the 
so-called West Indian i^each scale (Diets})!* lanatus). These results have 
since been repeatedly confirmed in experimentation against the San 
Jose scale. 
Winter remedies, therefore, which are thoroughly satisfactory on the 
Pacific Coast are of very much less value in the East, where the winter 
is at all wet and severe at least, and it is therefore necessary in con- 
sidering this subject to deal with the remedies for these two sections 
independently. 
METHODS OF CONTROL IN CALIFORNIA. 
The washes commonly recommended and for which notable success is 
claimed in California, are the lime-sulphur-salt solution, resin wash, 
and kerosene emulsion, ranking in estimation and common use in the 
order named. The lime-sulphur-salt wash is always employed during 
