376 MINNESOTA STATE HORTICULTURAL SOCIETY. g 
THE ARSENITES: LONDON PURPLE, PARIS GREEN, AND WHITE ARSENIC. 
These poisons are of the greatest service against all masticating insects, 
as larve and beetles, and they furnish the most satisfactory means of 
controlling most leaf-feeders, and the best wholesale remedy against the 
codling-moth. Caution must be used in applying them, on account of the 
liability of burning or scalding the foliage. 
The poisons should be thoroughly mixed with water at the rate of from 
1 pound to 100 to 250 gallons of water, and applied with a force pump and 
spray nozzle. In preparing the wash, it will be best to first mix the 
poison with a small quantity of water, making a thick batter, and then 
dilute the latter and add to the reservoir or spray tank, mixing the whole 
thoroughly. When freshly mixed, either London purple or Paris green 
may be applied to apple, plum, and other fruit trees, except the peach, at 
the rate of 1 pound to 150 to 200 gallons, the latter amount being re- 
commended for the plum, which is somewhat more susceptible to scald- 
ing then the apple. White arsenic does little, if any, injury at the rate 
of 1 pound to 50 gallons of water when freshly mixed. As shown by Mr. 
Gillette, however, when allowed to remain for some time (two weeks or 
more) in water, the white arsenic acts with wonderful energy, scalding, 
when used at the rate of 1 pound to 100 gallons, from 10 to 90 per cent. of 
the foliage; the action of the other arsenites remains practically the same, 
with perhaps a slight increase in the case of London purple. 
With the peach these poisons, when applied alone, even at the rate of 
1 pound to 300 or more gallons of water, are injurious in their action, 
causing the loss of much of the foliage. 
By the addition of a little lime to the mixture, London purple and Paris 
green may be safely applied, at the rate of 1 pound to 125 to 150 gallons of 
water, to the peach or the tenderest foliage, or in much greater strength 
to strong foliage, such as that of the apple or most shade trees. 
Whenever, therefore, the application is made to tender foliage or when 
the treating with a strong mixture is desirable, lime water, milky, but 
not heavy enough to close the nozzle, should be added at the rate of 
about 2 gallons to 100 gallons of the poison. 
With the apple, in spraying for the codling-moth, at least two appliea- 
tions should be made, the first after the falling of the blossoms or when 
the apples are about the size of peas, and the second a week or ten days 
later. The first brood of the codling-moth lays its eggs in the flower end 
of the young apple, and the worms upon hatching gnaw their way into 
the interior of the apple, and on sprayed trees get poisoned in so doing, ~ 
an infinitesimal amount being sufficient to destroy so minute a worm. 
The second spraying is for the purpose of destroying larve hatching from 
eggs which may be laid after the first spraying, as the arsenic is gradually 
washed off by rains. 
For the plum curculio on the plum, cherry, peach, etc., two or three ap- 
plications should be made during the latter part of May and the first half 
of June. The poison in this case is applied for the purpose of destroying 
the adult curculios, which hibernate and gnaw into the young growth of 
the trees, and even into the hard young fruit, before laying their eggs. 
The eggs are pushed under the skin so that the larve are not ordinaxiy 
affected by the poisoning. 
