72 THE SAX JOSE OR CHINESE SCALE. 
MEANS OF CONTROLLING THE SAN JOSE SCALE. 
INSECTICIDE APPLICATIONS. 
Active experimentation with different remedies for the San Jose 
scale was instituted by this Office promptly after the discovery of the 
occurrence of this pest in eastern orchards and nurseries. A full 
record of these early experiments is given in Bulletin No. 3 (new 
series) of this Bureau, pages 56 to 71. The subject of these experi- 
ments will not be gone into in detail. They covered the use of the 
lime-sulfur washes employed against the San Jose scale in California. 
the hydrocyanic-acid-gas treatment for orchards and nursery stock, 
lye washes, pure kerosene, kerosene-soap emulsions, resin washes, and 
soap washes. The earh T experience with the lime, sulfur, and salt 
wash was unfavorable, largely due apparently to the fact that the 
observations on the trees treated were not continued long enough to 
note the effect of the late summer results. Good results were 
obtained with the kerosene emulsions, and particularly with the soap 
washes, and the iish-oil-soap wash became one of the standard means 
of controlling the scale and is still among the best and safest washes 
to be used, altho rather more expensive than necessary, except where 
only a few trees are to be treated. 
The subject of remedies was promptly taken up by different experi- 
ment station entomologists in the East, and a vast bod} T of experimen- 
tal data is now on record in various station publications. The study 
of the subject of remedies has also been continued by this Bureau and 
reported in different bulletins. The lime, sulfur, and salt wash at 
first reported on adversely by us was afterwards demonstrated to be 
of real value, and experimental work was taken up, first by the Illinois 
Experiment Station, under Professor Forbes, and subsequently by other 
stations, and it has now come to be the generally accepted remedy for 
the San Jose scale. Without going at all in detail into the subject 
historically, it is sufficient for the purpose of this bulletin to reproduce 
the recommendations for the control of the San Jose scale substantially 
as given in the fourth revised edition of our Circular 42. 
In addition to the standard remedies mentioned below a great many 
proprietary substances have appeared, and some of these have some 
merit. The best of these are certain merchantable brands of lime- 
sulfur compounds, and oils which have been treated })y some secret 
process to render them miscible in water. The predominating con- 
stituent of the latter is mineral oil, and the resulting mixture, which 
is not apparentl} T an emulsior. is undoubtedly of value if used in suf- 
ficient strength to get the required amount of oil on the trees. There 
i> no advantage in using any of these compounds over the standard 
insecticides, and their greater cost U a distinct objection, together 
