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comes sooner or later. Only thirty or forty years 

 ago the potato beetle was so destructive throughout 

 the middle west that many people felt it would no 

 longer be possible to grow the potato successfully. 

 Yet natural enemies have developed which for a 

 number of years have held this insect in check to 

 such an extent that it has become unnecessary in 

 many cases to give even the ordinary treatments 

 for their direct destruction. In this connection it 

 should be emphasized that the natural enemies of 

 the potato beetle have done more to bring about its 

 present comparatively harmless condition than all 

 the poisons that have ever been used for its direct 

 destruction combined. Garden crops in many 

 respects are especially susceptible to insect and 

 disease attacks. A system of close and intensive 

 cropping is followed and the soil is occupied by 

 similar crops for a greater length of time each sea- 

 son than is common with most other crops. The 

 high value of the land usually devoted to truck and 

 market gardening and the more or less fixed char- 

 acter of the location devoted to the home garden 

 tends to discourage the proper rotation of the crops 

 usually necessary to hold these pests under 

 control. Time after time the gardener will con- 

 tinue to grow similar crops upon the same or closely 

 adjacent areas until it becomes practically impos- 

 sible to secure anything like profitable yields on 

 account of the ravages of insects and diseases. 

 From the very nature of things new insects and 

 diseases are bound to appear from time to time, 

 some of which will prove destructive for a period 

 and then gradually slip into the memories of the 

 past, only the remnants of the invaders remaining 

 as a reminder of the hordes that have passed. 



