CORN PESTS AND DISEASES 255 



of soda, are also useful as deterrents, particularly 

 when employed just before or after a shower has thor- 

 oughly wet the ground. They should be applied as 

 nearly as possible to the roots, and the earth should be 

 turned away from the plants for this purpose. This 

 remedy has the advantage of acting as a fertilizer as 

 well as a preventive of insect attack. As soon as 

 plants show signs of wilting, and this maggot is 

 known to be present in the field, the injured plants 

 should be promptly pulled and destroyed. These 

 methods of control have been used with success against 

 onion maggots and similar root-feeding species. 



The White Grab — Injuries of white grubs to corn 

 may begin as soon as the roots are fairly well started, 

 and will range according to the age of the plant, kind 

 of weather, and the age and abundance of the grubs. 

 There may be only a slight and temporary retarda- 

 tion of growth but a complete destruction of all the 

 corn is not uncommon. Lc:~ of the tap root exposes 

 the plant to severe suffering by early drouth, and it is 

 often so reduced in vigor from root injury that it fails 

 to form brace roots at the proper time, and hence has 

 so slight a hold upon the earth that it cannot keep 

 itself erect or recover itself after prostration. In any 

 case where the plant is yellowed, or dwarfed, or killed 

 outright, especially if these appearances be most 

 marked on the higher, lighter parts of the field, the 

 presence of white grubs may be suspected. As the 

 roots of an infested plant are evidently eaten away, 

 injury by the white grub is not easily mistaken for 

 any other. The presence of the insects themselves, in 

 the earth among the roots, is not hard to detect. If 

 they are not thus found where other evidence points to 

 them as the cause of the injury, they may frequently 

 be discovered by digging down a foot or two in the 

 worst injured tracts. 



