73 
Paris green not only rid the orchard of can kerw onus, but that the 
apples on the sprayed part were much less affected by the codling 
moth. It seems that other people used Paris green for cankerworms 
in Iowa, but there are no indications that they were alive to the fact 
that at the same time they were checking the codling moth. Prof. 
A. J. Cook, of Michigan, took up the idea and by a series of careful 
experiments clearly showed that the treatment was very effective 
against the codling moth. Forbes, Goff', and numerous others have 
at various times carried on spraying experiments with arsenicals, with 
results that show this to be the most effective and cheapest remedial 
measure that can be used. 
Spraying with arsenicals may be defined as putting a coat of any 
arsenical poison on the foliage and fruit of a tree, so that when the 
insects eat the foliage or enter the apples they eat some of this poison 
in their first few meals and are killed. Since the beginning of the 
practice of spraying there have been many important improvements 
in both spraying machinery and spra^nng solutions, which have ren- 
dered the process much easier than when primitive methods were in 
vogue. 
SPRAYING MACHINERY. 
There are as man}^ kinds of spraying machinery as there ar(^ condi- 
tions to be met in spraying operations. There are certain spraying 
outfits devised especially for orchard work, varying from the common 
bucket pump to rather complicated machiner}^ driven by gasoline 
engines. For a small home orchard or for an orchard of a thousand 
trees or less the writer would advise the use of a hand-power outfit. 
The capacit}^ and cost will depend primarily upon the size of the 
orchard, the size of the trees, and the rapidity with which it is desired 
to spray the orchard. There are many excellent types of spray pumps 
on the market, and no mistake can be made in jjelecting any of the 
outfits of the ])etter manufacturers, ])ut there are several })()ints whii'h 
should be insisted upon. The interior fittings of the pump sliould i)e 
of brass and should be arranged so that the inside of the cylindiM- can 
be easily reached in order that repairs may be made. The air cham- 
ber, which insures a steadier stream and acts as a reservoir of force, 
is almost a necessit}^ A pressure gauge upon this air chamlxM- will 
be of great value, as it will aid the man who does the ])umping to keep 
the pressure at about the sanu^ point. The })ump may ho mountiul 
upon a barr(d, wliich may be stood on (Mid or put on tlu^ side, or it 
ma}^ be mounted on a taidv or upon the wagon frame on which the 
tank is mounted. Tliese tanks iwo i)referably of wood, and should l)e 
of ver}' strong construction and securely bolted togi^ther with iron 
rods. Screens should be used to strain out particles wiiich would clog 
