SOME INSECTS AND MITES ATTACKING THE PEACH IN COLORADO 
By GEORGE P. WELDON 
The peach industry in the western slope region of Colorado is 
one of much importance, and the need for literature treating of a 
few insect pests and mites that the peach grower must reckon with, 
seems to be great enough to justify the publication of this bulletin. 
The novice in the business of growing peaches in Colorado very 
often begins with a mistaken notion that peach trees require no 
spraying. That notion has probably grown out of the fact that in the 
early history of orcharding in the State, spraying for the control of 
insect pests was confined almost entirely to apples. While the spray ¬ 
ing of peach trees may not be necessary every season, there are times 
when certain sprays are necessary in order that destructive pests 
may be controlled. One who hopes to make a success growing high 
grade fruit must resort to spraying whenever the prevalence of 
some insect pest demands it. It would not be wise to lay down set 
rules for the spraying of peaches, for there are too many factors 
that may bring about a marked increase or decrease in the numbers 
of certain pests occurring from season to season. For example, 
last spring' a very severe infestation of the common green peach 
aphis in the peach growing sections of Colorado, made it necessary 
that stringent methods of spraying be adopted. The previous 
spring the ocurrence of this pest was very general, but it was not 
abundant enough in most orchards so that it was necessary to spray 
for its control. Often a dormant spray of lime and sulphur, or solu¬ 
ble oil is beneficial in orchards where certain pests may be spending 
the winter. Too much, however, should not be expected of dormant 
sprays, and while there are insects that they may control very ef¬ 
fectively, there are others that will be controlled but partially or not 
at all. Very often the orchardist who uses a lime and sulfur spray, 
seems to lose sight of this fact, and because the spray does not meet 
with his expectations in controlling some certain pest, he condemns 
it for all of them. As a matter of fact he probably was paid for its 
use in the destruction of some other pest. 
the peach twig-borer (Anarsia lineatella Zell) 
One of the most common enemies of the peach in the United 
States, is the twig-borer, or “bud worm” as it is sometimes called. 
Its occurrence has been reported from most of the peach growing 
states of the Union, both in the East and West. 
In Colorado it has been known for a number of years, and while 
it is not a seriously injurious pest every season, there are seasons 
when it becomes exceedingly destructive, and is responsible for a 
great financial loss to those peach growers who do not adopt proper 
methods of control. 
