CONTROLLING INSECT PESTS 411 



in which this insect was introduced and the damage that it does 

 is referred to on page 507. Trained entomologists have been 

 sent to every foreign land where the gipsy-moth is known to 

 occur, and they have gathered and sent to this country all of 

 the different insect enemies of the pest that they could dis- 

 cover. Some of these have proved to be of no effect in our coun- 

 try, others aid a little, and still others give promise of being 

 important factors in the control of the moth. Those in charge 

 of the work do not expect to be able to find any one insect that 

 will do for the gipsy-moth what the Australian ladybird- 

 beetle did for the cottony-cushion scale, but they do expect that 

 if they introduce a great many parasitic and predaceous kinds 

 enough of them may work together to check the slow spread of 

 the pest and finally control it. 



Insects are often attacked by fungi and by certain bacterial 

 diseases. Sometimes these are very important factors in con- 

 trolling outbreaks of chinch-bugs, scale-insects, grasshoppers, 

 various larvae and other insects. But the conditions which 

 favor the development of the fungi or bacteria are often beyond 

 our control, and usually there is but little that we can do to 

 aid in the spread of these diseases. 



PREVENTIVE METHODS or CONTROL 



The natural enemies of insects do much, indeed, toward 

 controlling their numbers, but some of the worst pests require 

 the constant attention of the farmer or orchardist or he soon 

 sees his crops badly injured or totally destroyed. We can 

 never hope to get rid entirely of some of the pests, but by careful 

 management they may be kept in check so that they may not 

 reap the lion's share of the harvest. The most important 

 thing in dealing with insects is to begin early. Too often when 

 a pest makes its appearance the orchardist waits for a more 

 convenient season to commence fighting it. Meantime the 

 insect has had a chance to lay its eggs or, perhaps, to produce 

 several generations thus increasing many fold the number that 

 must now be fought. Until one understands how very rapidly 

 many insects multiply one can hardly realize the importance of 

 trying to get rid of a pest just as soon as it is found in the 



