86 
about two weeks later, when the majority of the larv?e are entering 
the fruit. There has been much discussion recentl}" in regard to dis- 
pensing with the spraying immediately after the blossoms have fallen. 
It has been found that the lary?e enter the fruit from one to two 
months after the blossoms haye fallen. In cases of bad infestation, 
where preyentiye measures haye been neglected, or there is an abun- 
dance of the insect, it might be well to make three spra3^ings while the 
second generation is entering the fruit. This period yaries with the 
localit}" and with the seasons in the same localitj^ ; but there are a few 
methods by which the time can be approximated with sufficient accu- 
racy, and in yiew of the fact that the time is variable the writer does 
not wish to recommend that the spraying be dispensed with until each 
locality is studied. Spraying may be ])egun immediately after the 
first new entrance holes of the second generation are found, or about 
twent}^ days after the date the maximum of the first-generation larvje 
are found under the bands read}^ to spin their cocoons. The lary^e of 
the second generation in southern Idaho usualh^ begin to enter the 
fruit the last week in Juh^, but the majority enter in August, and 
but few in September. The number of sprayings to be made against 
this generation depends entirely upon the success achieved against the 
first generation. It has been found quite definite^ that the injur}^ due 
to the second generation is much greater than that from the first gen- 
eration ; and if the injury due to the first generation is from 2 to 5 per 
cent the writer advises a third spra3dng for the second generation; 
but if the injury has been only 1 per cent or less, two sprayings will 
be found sufficient. The quantity of lime used in these late sprayings 
should be reduced to a minimum, as lime on the fruit depreciates its 
market value. 
Light showers wash but little of the spray from the tree; but if 
there is a heav}^ shower or continued rain, a large amount will be 
removed, and it will be necessary to repeat the sprayings as soon as 
possible. Lead arsenate is less afi'ected by rain than the other spray- 
ing compounds. 
HOW THE POISON KILLS THE INSECTS. 
Though Paris green has been used for spraying purposes for many 
years with success against the codling moth, it is only recently that 
any serious effort has been made to ascertain how the poison is 
obtained by the larvae. Slingerland was the first to answer this ques- 
tion with any degree of accuracy. According to him the spray lodges 
in the saucer-like calyx when the young fruit is erect after the blos- 
soms have fallen, and upon the segments or leaves of the calyx clos- 
ing the poison is held there for some time. As about 80 per cent of 
the larva? of the first generation enter the fruit through the calyx, it 
is easily seen how the majority of them would obtain some poison. 
