Walker Lake bulletin. (Hawthorne, Nev.) 1883-1926, 1922-10-21
DORMANT SPRAYING

Dormant spraying is directed against
those pests which may be most eff
fectively controlled during their rest
ing stage. The absence of foliage In
winter permits more thorough ap-
plicatlon and the use of stronger In
secticides than would be safe on trees
In leaf Sraying may be done any
time after the leaves drop In the fall.
or In winter when the weather warns
up to 40 f.. but Is preferable In early
spring when the buds are swelling as
at that time insects become active and
the spray Is more fatal to them
All sprays used on dormant trees
kill insects by contact rather than by
poisoning them through the digestive
tract. For this purpose many sub
stancts are used, all of which either
Interfere with the insects breathing
or corrodes its body or both. Those
commonly used for dormant spraying
misclble oils and soap sprays used un-
diluted or In emulsion.
OF these the lime-sulphur is dis
agreeable to prepare and use 1t
spreads and penetrates poorly, but is
safe. efficient, and has become the
standard dormant spray because of
its wide range of usefulness In con-
trolling nearly all insects that other
dormant sprays control. 1t remains
on the trees in an active condition
extending its usefulness into the sum-
mer as destroyer of insects, fungi,
and lichens which otherwise infest
controlling San Jose scale and many
related scale insects, the peartree
psylla. blister-mite. spider mite, and
several other pests.
For those with small orchards it
will probably always be cheaper and
better to use the commercial product,
being careful to follow accompanying
directions however lime-sulphur may
be prepared satisfactorily as follows
Use lbs. fresh stone lime 5000 or
Commercial ground) about gallons
more, calcium oxide); 10 lbs. sulphur
of water. Place a gallon of water in
the cooking vessel and start heating
1t; the lime and sulphur is then
placed in the vessel (the sulphur may
be made to a paste to avoid lumpi
ness), as most convenient. Stir them
vigorously while the lime is Stacking.
Add water as required to slack the
lime properly until the five gallons
are used. Boil about 80 minutes. stir
ring frequently, after which the solu-
ton should be of amber color. The
total volume of the finished product
should be 5 gallons. After straining
out all insoluble material this stock
solution can be kept Indefinitely If
mir is excluded from it.
For accurate work with lime-sulphur
a Baume hydometer to Indicate the
concentration is necessity. The form
ula given should yield solution about
26' Baume and for spraying San
Jose Scale should be used one part
to five of water. By using the same
formula with but Is as much water
the finished product will be more
concentrated and should measure
Sb gallons and have concentration
OF about 49, Baume. For use dilute
this strength one part to seven of
water. These strengths are for San
jose scale and are too strong except
for dormant trees.
Where aphids are troublesome 1t
ia often practicable to delay the dor
mnnt spraying until just as the buds
are breaking, and, by adding forty
per cent Nicotine Sulphate to the
lime-snlphur ut the rate of three
fourths pint per 100 gallons of spray,
effect combination treatment for
both scale and aphids.
In order to be successful spraying
must always he done throughly 1t
is necessary to reach every part of
the trees and for many of our worst |
PESTS the application must be made
at q definite and often limited time. !
The fruit grower owes 1t to himself
to study the pests affecting his trees
sufficiently to enable him to intelli-
gently combat them.