322 The Principles of Fruit-growing 



5. The necessity of spraying must develop a greater 

 watchfulness on the part of the fruit-grower for new 

 pests, for they are all the time appearing from foreign 

 countries, from adjacent states or geographical regions, or 

 from the wild. 



6. Inasmuch as every new necessity or new subject of 

 inquiry awakens new thoughts and expands the person's 

 relationships, so it becomes a means of enlarging and 

 educating the man. A concentrated invasion of the army- 

 worm is one of the very best means of waking up any 

 farming community and of setting every man, woman 

 and child to asking questions of every passer-by, every 

 agricultural editor and teacher, and experiment station. 

 The good effects of such an invasion are likely to last for 

 a number of years. It is surprising, as one thinks of it, 

 how easily people are scared by a bug! A strange insect, 

 which perhaps does not weigh a grain, will set a whole 

 community of able-bodied men agog, and may cause 

 as much downright fear and discussion as a political 

 revolution. 



The kinds of difficulties. 



There are three general types of difficulties or dis- 

 orders within the view of the discussion hi this chapter: 

 1. Attacks by insects. 



(a) The injuries of those insects that eat or 

 chew the parts of the plant, and which, therefore, 

 are killed by the application of arsenical and 

 similar poisons. Such insects are the whole tribe 

 of caterpillars, worms and beetles. 



(6) Attacks of insects that suck their food, 

 and which, therefore, are destroyed by caustic 

 applications that injure their bodies. All the 



