CONTROL OF CODLING MOTH IN COLORADO. 81 
portion of the orchard will sometimes give information of value. As 
a rule, however, fruit growers have neither the time nor patience to 
undertake a careful orchard survey. On account of seasonal varia- 
tions, calendar dates for making applications can not be depended 
upon, but a schedule based on certain intervals following the dropping 
of the blossom petals will usually result in timely spraying. 
In formulating the control of the coding moth it is very important 
that the approximate time of the first hatching of each brood of larvee 
and the relative number of worms that are developing from time to 
time be known. Complete and reliable data of this nature were 
obtained in the foregoing life-history studies, and with these data 
at hand it is believed that the most effective time for making the 
spray applications can be established. 
The spray schedules that follow are based on the life-history studies 
of 1915 and 1916 and take into consideration the time when each 
brood begins to hatch, the time when the larve are hatching in large 
numbers, as well as the time when hatching occurs in maximum 
numbers. Three sets of schedules, I, II, and II, all starting from the 
time 90 per cent of the petals have dropped, are presented in Table 21, 
by reference to which it will be seen that schedule I calls for five 
applications and is intended for orchards having a relatively light | 
infestation and for varieties on which the codling moth is not difficult 
to,control; schedule IT, six applications, for a medium infestation and 
for varieties on which the codling moth is moderately difficult to 
control; schedule III, seven applications, for a heavy infestation and 
for varieties on which the codling moth is most difficult to control. 
The codling moth is normally abundant in the Grand Valley, and 
apples such as the Ben Davis, Schackelford, and other susceptible 
varieties will usually require schedule III, or seven treatments, 
especially if from previous neglect or other cause the infestation is 
very heavy; whereas, under similar conditions of infestation, varieties 
hike theWinesap, on which the codling moth is more readily controlled, 
will require a smaller number of applications, as in schedules [ or II. 
The degree of infestation varies somewhat from year to year and in 
the different fruit districts, and, as previously stated, the control of 
this insect varies with the different varieties. For these reasons, no 
one schedule will meet the demands of all the growers, and it will be 
necessary for each individual to forecast in advance what his conditions 
are likely to be and spray accordingly. 
