447 
PARK AND CEMETERY. 
METHODS OF FIGHTING THE SAN JOSE SCALE 
The state at which cold water 
should be poured on to stop the cook- 
ing varies with different grades of 
lime. Some limes are so sluggish 
in slaking that it is difficult to obtain 
enough heat from them to cook the 
mixture at all, while other limes be- 
come intensely hot on slaking, and 
care must be taken not to allow the 
boiling to proceed too far. If the 
mixture is allowed to remain, hot fif- 
teen or twenty minutes after the slak- 
ing is completed the sulphur grad- 
ually goes into solution, combining 
with the lime to form sulphids, which 
are injurious to peach foliage. It is 
therefore very important, especially 
with hot lime, to cool the mixture 
quickly by adding a few buckets of 
water as soon as the lumps of lime 
have slaked down. The intense heat, 
violent boiling and constant stirring 
result in a uniform mixture of finely- 
divided sulphur and lime, with only a 
very small percentage of the sulphur 
in solution. It should be strained to 
take out the coarse particles of lime, 
but the sulphur should be carefully 
worked through a strainer. The mix- 
ture can be prepared in larger quan- 
tities if desirable, say enough for 200 
gallons at a time, making the formula 
32 pounds of lime and 32 pounds of 
sulphur to. be cooked with a small 
quantity of water (8 or 10 gallons), 
and then diluted to 200 gallons. 
The first application should be 
given when the young scale insects 
are beginning to crawl, which time 
will vary according to locality. In 
the locality of Washington this will 
be about the middle of May, earlier 
in the south, and later iir the north. 
This one treatment, if thoroughly 
applied, will do much to check the 
increase of the insect and to protect 
the trees from serious damage until 
the more thorough winter applica- 
tion can be made. A subsequent ap- 
plication should be given, if practi- 
cable, in the course of five or six 
weeks in order to destroy the young 
scales of the second generation. 
Under the heading “Petroleum-oil 
series” are to be included kerosene 
and crude petroleum, either pure or 
in emulsion, and the so-called misci- 
ble oils. 
Pure kerosene treatment. — Pure 
kerosene has been more or less rec- 
ommended for spraying trees badly 
infested with the scale, but it has 
never been very generally employed. 
There is no question of the efficiency 
{Concluded) 
of such an application in the destruc 
tion of the insects, but the great dan- 
ger of injury to the plants precludes 
its general application. Treatments 
of pure kerosene should be made 
only during bright days and should 
be applied through a nozzle with a 
very fine aperture. Only the mini- 
mum amount of kerosene necessary 
to cover the trees should be given, 
and care is necessary that the liquid 
does not puddle around the roots of 
the trees. 
Pure crude petroleum treatment. — 
Pure crude petroleum is used in iden- 
tically the same manner as pure kero- 
sene, and the same cautions as to 
its use should be remembered. The 
crude oil employed in the east is 
known as “insecticide oil” and has a 
specific gravity of 43 to 45 degrees 
on the Beaume scale. 
Kerosense emulsion (stock solution 
66 per cent oil). — Kerosene emulsion 
is made after the following formula: 
Kerosene (coal oil, lamp 
oil) gallons 2 
Whale-oil soap or laundry 
soap (or 1 quart of soft 
soap) pound 
Water gallon 1 
Dissolve the soap in boiling water; 
then remove vessel from the fire. Im- 
mediately add the kerosene, and thor- 
oughly agitate the mixture until a 
creamy solution results. The stock 
emulsion may be more conveniently 
made by pouring the mixture into the 
tank of a spray pump and pumping 
the liquid through the nozzle back 
into the tank for some minutes. The 
stock emulsion, if well made, will 
keep for some months, and is to be 
diluted before using. In order to 
make a 10 per cent spray (the 
strength for trees in foliage), add to 
each 1 gallon of the stock solution 
about 5 2-3 gallons of water. For 
20 and 25 per cent emulsions (for 
use on dormant trees and plants), 
use, respectively, about 2 1-3 gallons 
and 1 2-3 gallons of water for 
each 1 gallon of stock emulsion. 
■Agitate the mixture in all cases 
after adding the water. The prep- 
aration of the emulsion will be 
simplified by the use of a naphtha 
soap. No heat will be required, as 
the kerosene will combine readily 
with the naphtha soap in water when 
thoroughly agitated. Of naphtha 
soap, however, double the quantity 
given in the above formula will be 
required, and soft or rain water 
-should be used in making the emul- 
sion. In regions where the water 
is “hard” this should first be broken 
with a little caustic potash or soda, 
such as common lye, before use for 
dilution, to prevent the soap from 
combining with the lime or magnesia 
present, thus liberating some of the 
kerosene; or rain water may be. em- 
ployed. 
Crude petroleum emulsion. — Crude 
petroleum emulsion may be prepared 
in identically the same way as de- 
scribed for kerosene emulsion, sub- 
stituting crude petroleum for kero- 
sene. The same dilutions for winter 
and summer spraying should be made 
as prescribed for kerosene emulsion, 
but it should be noted that for sum- 
mer treatments of trees in foliage the 
kerosene emulsion is preferable, as it 
is less likely to cause injury. 
Miscible oils.— Under the heading 
“Miscible oils” are to be designated 
several proprietary preparations which 
are essentially petroleum oils with 
the addition of a vegetable oil and an 
alkali, to secure ready saponification 
with water. These come in concen- 
trated solutions and the spray is pre- 
pared by adding a specified amount 
of water. In point of convenience 
they leave little to be desired. Mis- 
cible oils are coming into increased 
use in place of kerosene or crude pe- 
troleum, either pure or in emulsions, 
and, have a distinct usefulness as 
winter sprays about the same as have 
the concentrated lime-sulphur solu- 
tions. As has been indicated, the pe- 
troleum oils are at times the cause 
of injury to twigs and fruit buds, and 
it is a question of judgment whether, 
under conditions of severe scale in- 
festation, the petroleum oils or the 
sulphur solutions should be used. The 
petroleum oils, on the whole, are 
more effective and the danger of in- 
jury from them is less to pome than 
to stone fruits. 
The pi acticability of making misci- 
ble oils at home has been investi- 
gated by Prof. C. L. Penny, and he 
has shown it to be entirely feasible, ' 
as detailed in the publication cited in 
this bulletin. 
SOAP WASHES. 
Practically the only soap wash 
which has come into extended use 
against the San Jose scale is that 
made from whale-oil soap. This is 
used mostly on dormant trees, the 
soap being employed at the rate of 
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