59 
be the case in actual practice, and probably much more so. It is pos- 
sible, therefore, that the death of the trees in some instances was due 
to the collection of the oil in the cavity formed about the trunk by the 
swaying of trees in the wind, which, as will be shown later, has had 
disastrous results in California with the emulsion even. Others have 
reported the use of oil on trees without injurious effects in some 
instances and in others with injurious effects, so that pure oil as an 
insecticide is one to be used with caution and with full appreciation 
of the fact that the death of the plant may result. 
In this connection I wish to call attention again to the lastest per- 
fected spraying apparatus made by the Deming Company for the mix- 
ing of oil and water in the act of spraying. This apparatus, which is 
a slight improvement on the old and made to use with a bucket pump, 
we have experimentally tested, and it seems to give with considerable 
regularity the proper percentages of oil and water called for by the 
indicator. As one of our principal objections to this contrivance as 
formerly constructed was the fact that it was not uniform in this par- 
ticular, the present apparatus seems in a measure to have invalidated 
this objection. Kerosene mixed with water, however, is not nearly so 
powerful an insecticide as the kerosene soap emulsion. It does not 
remain nearly so long on the plant and is not nearly so effective an 
insecticide at the same strength of oil. The heavier soap or milk 
emulsions kill more effectively, which perhaps is explained by the 
heavier liquid actually bringing more oil in contact with the insect and 
also by its greater permanency. 
E 
i“ 
- 
. 
ie 
sy 
er ae a 
USE OF KEROSENE EMULSION IN CALIFORNIA. 
This insecticide is used to a very considerable extent in California, 
much more so in recent years than formerly. It is the principal insect- 
icide used in the district about San Diego, and is also used extensively 
at Santa Barbara and to a less extent elsewhere in the State. The 
necessity for the use of very large quantities of insecticides in Califor- 
nia has led to the establishment by private parties in several instances 
of steam or gasoline plants for the wholesale production of this insecti- 
cide. Probably the first extensive manufacturing plant of this sort 
was set up by Mr. W. R. Gunnis, county horticultural commissioner, of 
San Diego, who manufactures the emulsion by the aid of a smail engine, 
doing all the work of heating, churning, etc., by this means. With coal 
oil at 11 cents per gallon, he is able to produce the emulsion at a charge 
of 13 cents per gallon in the undiluted state, which makes the wash as 
applied to the trees, diluted 7 times, cost a little over 14 cents per gal- 
lon. In his district, Mr. Gunnis claims that the loss from scale insects 
has been reduced from 79 per cent. to 7 per cent., chietly by the use of 
this wash. 
At Santa Barbara the superintendent of the Las Fuentos ranch, Mr. 
Frank Kahles, has set up a very large plant for the manufacture of 
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