356 INSECTS AFFECTING VEGETATION 



Permitting Hogs or Other Animals to Grub in Orchards, Wind- 

 breaks, and Tree Groves. The large destructive Willow Saw-fly hi- 

 bernates just under the surface of the soil, or even above it under 

 rubbish. Their larvae are readily detected and greedily eaten by 

 hogs, skunks and shrews. 



Concentrating Insects Upon Favorite Food Plants. This can 

 be done either by causing some plants in the outer rows to appear 

 earlier than the rest, and thus concentrating upon them the great 

 majority of the noxious insects, or by growing some rows of varieties 

 preferred by them. In either case the insects thus concentrated upon 

 a few plants can be much more readily killed than if scattered over a 

 large field. 



High Culture. By manuring or by working the soil more thor- 

 oughly the plants grown upon it are stronger and more able to re- 

 cover from damages caused by insects. Young plants of wheat, eaten 

 down to the ground by young locusts, will recover and still produce a 

 good crop if the land was in a prime condition. 



Refraining for One or Two Years from Crops Badly Infested. 

 Chinch-bugs in our southern counties forced farmers to abandon the 

 growing of wheat for a number of years. Lack of food, and other 

 causes, destroyed the insects, and wheat can again be grown for some 

 seasons. Rotation of crops has a similar, but not so thorough an 

 effect upon insects. 



Selection of Varieties Less Liable to Attack. This is a very im- 

 portant natural remedy, and can be applied in many cases, but in 

 other cases such unpalatable varieties are as yet unknown, and it is 

 the office of the Experiment Station to make the necessary efforts 

 to find them if they can be discovered. Diversified farming in in- 

 fested regions is also very important as in this case it is never likely 

 that all the crops will be destroyed, since nearly all insects are de- 

 pendent for food upon certain plants, and neither can nor will eat 

 others. Growing of unpalatable crops in place of others greedily 

 eaten is also a similar natural remedy. 



Late Sowing. This is also an excellent method to prevent cer- 

 tain noxious insects from causing injury, and can be applied in many 

 cases and to various crops. Late sowing of peas will prevent the Pea- 

 weevil from depositing eggs upon such plants, because the weevils die 

 before the plants are flowering. Keeping seed-peas longer than one 

 year in a tight sack will have the same effect with most species. 



Early Sowing. This, if done properly, will enable the plants to 

 attain such growth and strength as to be beyond serious injury. 



Late Plowing; Early Plowing. Both methods are sometimes of 

 great value to protect crops grown upon fields thus treated. Late 

 plowing will disturb and kill many insects that are hibernating in 

 the soil. Tender insects and pupae that can not move are thus killed. 

 Early and repeated plowing will expose many insects otherwise hid- 

 den m the ground to the attacks of birds, shrews and other animals. 

 The full-grown larvae and pupae of wire-worms are killed by dis- 

 turbing the soil late in the fall. Young locusts can not reach the sur- 

 face of the ground if the eggs are plowed under, Late plowing of 



