64 



A complete report of this investigation is now in course of prepara- 

 tion, and at this time it is thought appropriate to give some of the 

 more interesting and important results obtained by a study of the life 

 histor}^ 



In 1897 Professor Card noticed that the lnvviv which hatched from 

 eggs laid upon the leaves would eat out considerable portions of the 

 leaves before entering the fruit. This was stated to occur more fre- 

 quently in cages than in the held. 



In Farmers' Bulletin No. 127 of the Department of Agriculture, Mr. 

 Marlatt notes these observations and suggests that the larva3 are killed 

 by eating the leaves. 



Professor Cordley found the past season that two 3'oung larvte just 

 hatched tunneled into the midrib of the leaves, and one of these fed 

 until it was about full grown. In a letter to the writer he concludes 

 as follows: 



I believe that with careful attention it could have been brought to maturity on a 

 diet of leaves alone. When one considers that it lived and grew for more than three 

 weeks upon leaves that had been severed from the tree, sometimes for several days, 

 and that it was apparently more thrifty between June 16 and 25 than in the earlier 

 days of its existence, one must acknowledge that, while the proof is by no means 

 positive, the indications are that codling moth larvye may fully develop on a diet of 

 perfectly fresh apple leaves without ever having tasted fruit. 



The writer has man}" times taken both young and old larvre and fed 

 them for some time upon leaves, and they seemed to thrive upon this 

 diet, but on account of lack of care and attention I never brought any 

 to maturity. The older larvffi eat the leaves by folding them together 

 and eating out irregular holes. Many observers have noted that the 

 larvii? feed for several da3's in the cal3'x when they enter at that place. 

 On examination of the tissue of the calyx one can see that its struc- 

 ture is much like that of leaves. General results obtained ]\y spray- 

 ing were very satisfactor}", and the efficiency of the spraying can not 

 be accounted for b}^ the entrance holes in the fruit in which the larvae 

 are found to have died. In the spring a great majority of the eggs 

 are laid upon the leaves. In one instance one female moth in confine- 

 ment laid 20 eggs upon the leaves and 1 upon the fruit, while another 

 laid 22 eggs upon leaves and 2 upon the fruit. Professor Cordley 

 writes that he has no record of a single egg being deposited upon the 

 fruit until after it has lost its pubescence. Later in the season, par- 

 ticularly with eggs of the second generation, the proportion of eggs 

 upon fruit and leaves are foiuid to vary greatly. Some countings 

 made in August, 1902, gave an average of 50 per cent on fruit. 



Taking all the data into consideration, the writer believes it safe to 

 conclude that the larvw of the codling moth can reach maturity on a 

 diet of leaves alone. To what extent this occurs under normal field 

 conditions yet remains to be determined, but the writer believes that 



