54 
Colorado Experiment Station 
to cover all their food with the poison; if they are to be killed with 
a contact spray, it must hit the insect. The first requisite is a man 
to hold the nozzle who knows what thoro spraying is and is not 
afraid to do it. The second is a pump that will give plenty of press¬ 
ure, and the third is a nozzle that will break the liquid into fine 
particles. The liquid should be strained into the barrel or tank, so 
there will be no solid particles large enough to clog the nozzle. 
With the poison insecticides, the best results follow when the leaf 
is covered most completely and uniformly with the spray mixture. 
This is best done by making a spray fine enough so that it will fall 
on the leaf in mist-like particles and dry there. The aim should be 
to cover every leaf in this way. In order to do this, it will be neces 
sary to spray the tree from all sides and angles. Do not make the 
mistake of having the spray so fine it will not carry into the tree 
enough to reach the inner limbs. 
In applying the contact insecticides, the spray should be coarse 
enough to wet the insects when it strikes them and to penetrate the 
woolly covering that some insects have. 
In applying the first spray for the codling moth, when the object 
is to fill the calyx cups of the little apples with the liquid, the best 
results are obtained with a medium coarse spray that will thoroly 
wet all parts of the blossom end of the fruit. By this is not meant 
a spray made up of coarse drops, but one that is broken into fine 
particles, but still with body enough to carry 8 or lo feet from the 
nozzle without going into a mist or fog. 
It is important to have the nozzle on an 8 foot rod, at least, and 
at an angle of about 30 degrees. This will permit one to reach the 
higher parts of a tree and spray them from different angles. When 
spraying large trees, the work is greatly facilitated by having a 
tower arranged on the machine so that one man can spray from an 
elevated position. This is especially important in putting on the 
first codling moth spray. At this time a large percent of the little 
apples are directed upward and the spray can be thrown directly 
into the calyx cups. 
NOZZLES TO USE 
There are two types of nozzles that are used extensively, the 
Bordeaux type that throws a flat spray, the fineness and volume of 
the spray being regulated by the size of the stream that is thrown 
against a flat face of the nozzle; and the Vermorel or whirl-pool 
type that throws a cone shaped spray which may be graded from 
coarse to fine, depending upon the pressure and the size or the aper¬ 
ture in the plate. The latter have been greatly improved by giving 
