Show crop rotation kills many insect pests when one sees the annual loss to crops and property caused by insects he is inclined to think that crop pests are getting more numerous and destructive from year to year it is a fortunate farmer who has not experienced a loss from these six footed animals the hessian fly takes a yearly toll of millions from american farmers the chinch bug has ravaged our corn and wheat the past 50 years to the extent of several hundred millions of dollars figures in this state on codling moth sugar beet webworm web worm and grasshoppers would be equally staggering moreover several human diseases are carried only by insects all can testify that gnats flies mosquitoes etc are an annoyance no yance where large of one kind of crop are grown one can naturally look for increased insect injury from year to year unless preventive and remedial measures are taken the number of species that attack one plant is often large about attack clover affect corn and the apple the first year the crop is grown a person may assume that a few injurious insects will find their way into the field and do practically no injury the insects will hibernate or pass the winter near by and find conditions unusually favorable for development the next year should the same crop remain on the land each succeeding year the injury can be expected to increase on the other hand where crops are changed the insects will emerge from winter quarters and find no food at hand this will necessitate a search for it and only a few of the insects that successfully pass the winter will find their way into the new field this is especially true of insects that pass the winter in the larval or worm stage and are not able to travel far of course all insects cannot be controlled by crop rotation |