160 TWENTY-NINTH FRUIT-GROWERS' CONVENTION. 



egg-laying habits of the moth. The commonest conception, and the 

 one which is still found in many of the books on entomology, was that 

 the egg was laid at the blossom end of the apple at about the blooming 

 time, but curiously enough this statement was made without a particle 

 of actual observation to support it. I need not go into the detail of the 

 steps in the discovery of the egg-laying habits and the changes made 

 necessary in the theories regarding the reason for the effectiveness of 

 spraying with arsenicals. 



In the Pajaro Valley this season the moths did not begin to emerge 

 in numbers until the fruit was of considerable size, and early in the 

 season the eggs were not laid upon the fruit at all. It has been known 

 for some time that many codling-moth eggs are found upon the leaves 

 as well as the fruit, but no observations previous to those of the present 

 year appear to have been made early in the season. The egg, as many 

 of you are aware, is a flat disk, about the size of a pin-head, which is 

 cemented fast to the surface of the leaf or fruit, and is so transparent 

 that the green color shows through and renders it very difficult to see 

 one except when looking in the right w^ay. Being cemented to the 

 plant it will be evident that only the smooth surfaces of the leaf or 

 fruit would be suitable for this purpose. Indeed, it was extremely rare 

 to find eggs anywhere except upon a smooth surface. Now, early in 

 the season when the first eggs are being laid the whole surface of the 

 apples and young leaves is covered with downy hairs.» A few of the 

 older leaves soon become smooth on the upper surface, and it is here 

 that the first eggs are laid. These old leaves may be, perhaps usually 

 are, far away from the fruit, but the most careful search of the surface 

 of the fruit and of the young leaves failed at this time to show any 

 trace of the eggs. Later, but still during the time of the hatching of 

 the winter brood of moths, the under side of the leaf becomes smooth, 

 when eggs may be found beneath the leaves, as well as above them, 

 though never as abundant as on the upper side. Finally, the fruit 

 itself also becomes smooth, especially on the upper exposed side. As 

 soon as this is the case the moths show a decided preference for the 

 fruit, and while the eggs are still laid in considerable numbers on the 

 leaves, the number on the fruit is out of all proportion to the amount 

 of surface exposed. This preference is maintained throughout the year 

 with the later broods, although the insects never cease to lay upon the 

 leaves, but deposit perhaps a third of their eggs in such situations. 

 The part of the apple last to become smooth is the hollow of the two 

 ends, and it is the rarest thing to find eggs in these situations, even 

 after they do become smooth. The commonest place to find the egg is 

 upon the side most exposed, and they are laid here at random without 

 regard to any peculiarity of the apple and sometimes in considerable 

 numbers. Half a dozen eggs upon a single apple is no uncommon 



