Spraying Experiments in Nebraska 
25 
I larvae began to hatch. ^ At this time the calyces point down and 
the spray should be directed against the fruit and foliage from all 
angles to insure complete covering. Normally this spray should 
be applied 14 to 21 days after the petals fall. 
Next to the calyx-spray the second -brood application is the 
most important. It should be applied just as the second-brood 
larvae begin to hatch, and in the same manner as for the preceding 
spray. 
Two pounds of lead to 50 gallons of spray was found to be as 
efficient as more. There is some indication that the cluster-bud 
spray in some of the schedules had some effect in controlling codling 
moth injury, but there is not enough evidence of this to warrant 
making any statement to that effect. 
THE PLUM CURCULIO 
In the past the plum curculio has not been considered as a 
particularly serious pest in Nebraska, except on stone fruits. 
However, from certain sections of the state so much damage has 
been reported of late years that it was deemed expedient to 
attempt to evolve some means of controlling the insect. Accord- 
ingly, a study was made of the effects which sprays, applied for the 
control of codling moth, would have on the plum curculio. 
The primary injury done by the curculio consists of small holes 
made in the apples in feeding and for depositing eggs. However, 
: this is only a small part of the injury. These punctures cause the 
i I fruit to become ill-shaped and knotty, and admit fungi. 
The beetles pass the winter as adults under trash and rubbish, 
[ and emerge and begin feeding on the new leaves before the blossoms 
c open. As soon as the fruit sets they begin feeding on it and de- 
6 positing their eggs. 
^ There seems to be a division of opinion among workers along 
this line as to whether any feeding is done by the curculio before 
iThe only way to know definitely when this and the second-brood spray should be applied is 
I I to observe the development of the moths and larvae each season. The importance of this may be 
readily seen by comparing the charts for the different years and noting the different dates of 
■i hatching of the larvae. 
J There is a correlation between weather conditions and the development of the codling moth. 
Not only are all of the periods of the life cycle of the insect shorter in midsummer when the days 
I are long and hot than they are earlier in the spring, but they are shorter thruout and the insects 
I. develop much more rapidly during hot, dry seasons like 1914 than in cool, moist weather of seasons 
like 1915. Temperature seems to be the determining factor. During the time when observations 
' were being taken, the larvae were always found more lively on warm than on cool days. In fact 
on one occasion when the temperature suddenly dropped to 40 degrees the larvae remained almost 
" entirely inactive. It was also noted that the emergence of the moths was closely correlated 
with the temperature. The moths would emerge in large numbers during bright, warm weather; 
and during a drop in temperature would cease emerging altogether, to begin again as the 
! temperature rose. 
By collecting larvae early in the spring, keeping them confined until they pupate and emerge 
as moths, then repeating the operation for the second brood and the third brood, if necessary, and 
by noting weather conditions, every orchardist should be able to spray so that he may secure the 
highest efficiency from the materials used. The best materials will give at best poor results if 
used at the wrong time. 
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