INSECT ENEMIES OF PRINCIPAL CROPS 163 



conditions always consult the economic literature dealing 

 with particular species.* 



For record of your observations, write up for each experi- 

 ment an account of the nature of the injury, the habits of 

 the pest, and the method of its control. 



LESSON 15 



Wormy Apples 



If it is autumn, and if near by there is an old apple tree 

 carrying a load of fruit (whether good or bad fruit does not 

 matter), let us examine the scarsf on the apples for thus we 

 may learn what are the principal enemies of the apple fruit 

 and how different are the ways in which they do their work. 



First, we will gather the apples — all of them; good, bad 

 and indifferent. Or, if there be too many, then all that are 

 on some natural division of the tree. Then we will arrange 



* See page 150. 



t Since it is not always easy to identify the insect by the scars it has 

 left, we must be careful in gathering the apples not to throw away certain 

 bits of evidence, especially these two sorts: 



1. Clusters of numerous dwarfed apples having skins puckered toward 

 the blossom end, and borne on very tough stems; these clusters should 

 be kept together, for they are the sure signs of the work of aphids. 



2. Apples with leaves fastened against them by means of silken threads; 

 each apple should be kept with its leaf attached until we are ready to study 

 it; for this is the sign of the bud moth. With these precautions observed, 

 this study may be kept in reserve for a rainy day, and all the apples 

 gathered and brought indoors for study. 



