
23 
the wind, and accumulation of the insecticide at this point, unless 
precautions be taken, may result in the death or injury of the plant. 
Under these conditions it may be advisable to mound up the trees 
before spraying and firmly pack the earth about the bases. Care 
should be taken in refilling the tank that no free oil is allowed to 
accumulate gradually in the residue left at the bottom when spraying 
with emulsions or oil-water mixtures. 
Miscible oils—It will be noted that the difficulty to be overcome in 
the use of oils is to effect their dilution to render them harmless to 
the plant. This dilution is effected with great accuracy by the kero- 
sene-soap emulsions, and less accurately by the mechanical emulsions 
of oil and water. There have appeared during the last few years 
various so-called miscible oils, which readily and permanently mix 
with water, and can be applied with the same readiness and accuracy 
of strength as the emulsion of kerosene and soap. These oils have 
for their principal ingredient some form of petroleum rendered solu- 
ble by the addition of a percentage of vegetable oils and cut or sapon- 
ified with an alkali, and they are, in fact, a sort of liquid petroleum 
soap. They are sold under various trade names. They have the 
disadvantage of costing a good deal more than the standard emul- 
sions or the lime-sulphur wash (see p. 24), but have the great advan- 
tage of being always ready for immediate use without troublesome 
preparation. They can not be diluted for winter applications against 
scale insects with more than 10 or 15 parts of water to give good re- 
sults, and there is some danger of injury to the trees if they are care- 
lessly or excessively applied. They have, however, a very useful place, 
und especially as furnishing a good insecticide where only a few 
trees are to be treated and the owner would probably not go to the 
trouble of preparing an emulsion or the lime-sulphur wash. They 
have been so far principally used against the San Jose scale as dor- 
mant tree washes. 
THE RESIN WASH. 
The resin wash has proved of greatest value in California, particu- 
larly against the red scale (Chrysomphalus aurantii Mask.) and the 
black scale (Saissetia olew Bern.) on citrus plants, and the last named 
and the San Jose scale (Aspidiotus perniciosus Comst.) on deciduous 
plants, and will be of use in all similar climates where the occurrence 
of comparatively rainless seasons insures the continuance of the wash 
on the trees for a considerable period, and where, owing to the 
warmth, the multiplication of the scale insects continues almost with- 
out interruption throughout the year. Where rains are liable to 
occur at short intervals, and in the Northern States, the quicker- 
acting and stronger kerosene washes and heavy soap applications are 
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