1G 
may be for scrubbing the trunks ami branches of a tree, I cannot con- 
scientiously urge it as, on the whole, satisfactory, particularly as it is 
known to stain the fruit, and because of the many different grades, 
varying in their effect and in their value, which are upon the market. 
Potash and soda lye injure the tree more than kerosene does and do not 
destroy the insects as well, admirable though they are as washes in 
weaker solution for some other purposes. The action of sulphurated 
lime (flowers of sulphur boiled in milk of lime) is very similar to that 
of caustic potash. 
Notwithstanding the kerosene emulsions, in proper proportions, have 
proved so satisfactory against the scale-insects of the Orange in Flor- 
ida, the}' have, as a rule, failed to win the good opinion of the orange- 
growers in California. I have always believed the want of success in 
this State with the kerosene emulsions was due to imperfect preparation 
of them, or to imperfect application. I was inclined to give some cre- 
dence to the theory advanced by my old-time friend, Prof. E. W. Hil- 
gard, who is so keenly alive to everything that interests you, and whose 
services have been so invaluable to the agriculture and horticulture of 
the State, namely, that the dryness of the atmosphere in California 
induced a more rapid evaporation of the kerosene, which may partly 
account for the difference in experience between the Atlantic and Pa- 
cific. For these reasons I had long desired to make a series of ex- 
periments in California, and finally, last year, did have such a series 
carried on by Messrs. D. W". Coquillett and Albert Koebele. It were 
difficult to find in the whole State two gentlemen combining in the 
one instance more care and reliable entomological capability, and in 
the other more industry, earnestness, and enthusiasm, and this I say 
without desire to flatter, but as evidence that their experiments, so far 
as they went, were trustworthy — in fact, I may say, the most careful 
and thorough that have hitherto been made. These experiments ex- 
tended over a period of three months in the spring and three months in 
the autumn, and the detailed reports which these gentlemen have made 
will be published in connection with my forthcoming annual report. 
They show that the kerosene emulsions must still be placed at the head of 
the list of washes, not only for ordinary scale-insects, but for this Icerya 
or Fluted Scale. Among the different substances thoroughly experi- 
mented with were caustic potash, caustic soda, hard and soft soaps, to- 
bacco, sheep dip, tobacco soap, whale-oil soap, vinegar, Paris green, 
resin soaps and compounds, and so on. It is impossible to give even a 
digest of the very many experiments, and the varying results obtained 
with the different washes. It suffices to say that the kerosene emulsion 
diluted with from eight to ten parts of water was found to kill all the 
eggs as well as the old females, and that. even when used still stronger, 
it left the tree uninjured. Mr. Coquillett reports with reference to the 
much-praised caustic soda, that it has no effect on the eggs of this scale 
even when applied so strong as to burn the bark and kill all the leaves. 
