106 FRUIT-GROWING 



method of poisoning the sap of the trees with- 

 out killing the tree we would have an easy 

 means of eliminating these little oil prospectors 

 which set up their derricks on our fruit trees. 

 The chewing insects are more easily handled 

 as they feed from leaf to leaf and have many 

 chances of connecting with the poison we put 

 out for them. The fungous diseases are per- 

 haps the worst of the lot for they are passed 

 around from tree to tree by means of minute 

 spores so small that we can not see them. They 

 are the invisible enemy that lurks for us in the 

 shade of every leaf and on the twigs of every 

 tree. 



Sucking insects comprise the whole list of 

 scales, the various plant lice, the apple red bug 

 and other insects of its kind. The scales have 

 perhaps attracted more attention than any oth- 

 ers of this whole group because their method of 

 attack is so spectacular that they are not easily 

 overlooked. We have many native scale in- 

 sects most of which are of minor importance 

 because we also have parasites which feed upon 

 them and thus hold down their numbers. It is 

 the imported pests that we fear most and justly 

 too, because they as yet seem to have little para- 

 sitic control. Chief of these is the San Jose 

 scale, the "yellow peril" of the fruit-grower. 

 It was introduced from China many years ago 

 and has become widely distributed over the 



