THE WAR ON INSECTS 303 



borers approach full size. Then the infested plants are 

 taken out and destroyed, borers and all, leaving the 

 others free with prospects for only a very small brood 

 of moths for next season. 



That introduces the matter of clean culture. It 

 has been shown, elsewhere, that some of our well-known 

 pests pass a portion of their life, and sometimes an im- 

 portant one, on wild plants allied to the crop grown, 

 and these serve to tide it over from one season to an- 

 other. Clean cultivation rids the farm or garden of 

 these wild plants and makes it more difficult for them 

 to survive. So a great many species live through the 

 winter on the remnants of the crop they infested, and 

 were these destroyed, the hibernating forms would be 

 destroyed with them. It is a good general rule, when 

 you are done with a crop, get it off as soon as possible 

 and burn all left-overs that might shelter injurious 

 insects. Stems of cotton, cucurbs, potatoes and toma- 

 toes are among those with insects so controllable. 



If in all orchards all dropped fruit could be kept 

 picked up and destroyed, injury from codling moth 

 would be at once reduced more than one-half; plum 

 curculios would soon cease to be important, and fruit 

 flies would lessen materially. Some work is done along 

 this line in large orchards, but as a rule the insects in 

 dropped fruits are allowed to develop at will. 



Farm animals can be utilized much more exten- 

 sively than they have been. Sheep and hogs in an 

 orchard are great helps in disposing of dropped fruits 

 and of such insects as come to the surface. A drove 

 of hogs in a sod field infested with wire-worms and 

 grubs will tear it up and dispose of a very large number 

 of the specimens if aided by a few shallow furrows to 

 give them a start. Chickens, turkeys and guineas are 

 great insect feeders and can be trained to follow the 



