The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1901-04-07
WASHES AND SPRAYS
FOR FRUIT PESTS
Experiments Made at Different
Government Stations.
USE OF PARIS GREEN
SUCCESS FOLLOWS APPLICATION
OF KEROSENE.
USE OF PARIS GREEN
lspeclaI Corresnandence.l


terest TO farmers and fruit growers re-
Earding experiment station work has just
been issued by the department OF agri-
culture. Discussing The subject of i'm
secticides the bulletin states that 1t has
been observed by entDmologists and fruit
growers that the results obtained by the
use Of Paris green varied 60 a consider
able extent. The California stanton has
recently made some investigations of
Paris green as ail insecticide- as well as
Of the damage to foliage often noted as
a result of ITS use.
As a result Of these studies. three
classes Of unsatisfactory Paris green are
recognized: Bogus, adulterdted and low
grade. BY bogus Paris green is meant
ouf-and-oiIt limitations of the substance
IN which the color is due TO other SUD
s. little trace Of either copper or arsenic,
which are the essential constituents OF
pure Paris green. 1t is nos believed that
much Paris green Of this nature IS upon
the market.
that Ia which some other cheaper ana
usually nOn-poisonouS substance mas peeh
added for the purpose of increasing the
weight, for eX5mpiei gypsum ana I.EuI.
JSy a low grade Paris green is meant
Paris green which contains a low per
rentag6 Of arsenic. To raise the percent
age Of arsenic in such grades of Paris
green it is customary to add free arsen-
iOus acid Cwhite arsenic). Such a mixture.
iibiie 10 considerable extent in watec,
and for this reason is likely TO injure the
foliage. This injury cannot always oe
prevented BY the addition of lime. which
has been generally recommended Tor TINS
purpose.
Standard for Paris Green.
In several states laws nave been passed
green green. These laws. however. SIMPLY re-
qulre that Paris green shall contain a
vii hon rs
dent from the above facts that to be OF
the greatest benefit to fruit growers the
the form OF the arsenic in the Paris
green. One of the chief advantages OF
pure Paris green as an insecticide is its
Slight solubiiity in water and the cOnse-
Quent possibility OF using IT IN consider
able quantities without inluring the tol-
1age OF plants When, however, deaclehcY
in arsenic content is made with a sol
uble form OF arsenic, tha value OF the
substance as an inse1ticide Is greatly re
duced.
There is considerable difference Of
opinion as 20 the extent of such adullera-
lion OF twenty-tOur samples % Paris
green examined during 1895 by the New
York state station I'm compliance with
the state law providing for inspection OF
this article, only one or Two showed cyl
sience of admtxture of white arsenic.
This station states that the color OF
Paris green is changed TO such an eX-
text by addition of white arsenic or other
SIMILAR materials that one can usually
detect an adulterated article BY its APP
pearance. Paris green Of good quality
IS intensely bright green and uniform.
When adulterated, the green loses some
tl,f,rv - - fDfar,-it,r nd * eyr., wish and
IS not always uniform.
The bulletin further states that during
the past few years the San Jose scale has
caused so much alarm among the fruit
growers Of this and other countries that
CntOmOlOgistS have devoted large
amount OF attention 70 the development OF
effective methods of controlling IL. The
unusually energetic efforts which have
been put forth in this direction have re-
suited in the production of methods which
are useful against "A number of other in
scots as well as against the San Jose
Washes for the Scale.
Besides the method of fumigation with
bydrOcyanic acid gas, various washes sni
spraying solutions have been al llied with
more or IcSs success against scare lnseets-
Kerosene oil, diluted and uudiluted, has
been experimental with in a number or
states, and recently crude petroleum has
attracted attention as a remedy against
the San Jose scale A rather extensive
series Of experiments with this substance
was recently conducted by Professor J. 3.
smith at the New Jersey station the re-
suits of which were such that a number
OF fruit growers were asked to make e,s-
periments on their own orchards in order
10 determine whether the crude oil could
be safely used as spray or wash by the
average horuculturisI.
The trees treated with the crude oil in
CIuded all the ordinary fruit trees except
the cherry. and numbered about 1000. the
crude OH was applied as a wash and as a
spray In the form of "a spray II was used
u6diiutcd and also diluted with water in
various proportions These .tre8 tnents
were al first made during the winter. hut
later the oil was tried summer spray.
Considerable injury resulted, however
from its use upon the foliage of fruit
trees during thc growing season. The sta
ton Therefore concludes that Crude pc
troleum is not suited for a summer apDn-
cation, either pure CT diluted" but that
Tor Use in winter lit is fully as effective
against scale insects as kerosene, and Is
harmless TO the most tender varieties and
on the Youngest trees. As the
oil remains on the surface for a long time
u makes no difference whether Il is put
ON undiluted or mixed with water
When the crste oil is applied in an un-
diluted FORM the station recommends that
an apparatus which makes a fine spray be
used for it's applica ton When this - ,Dt