Potato Insects and their Control 



181 



adult beetle or as white grubs. It takes two or three 

 years to complete its life cycle. The adults lay eggs in 

 sod ground in June which hatch in about two weeks. The 

 larvae or grubs feed on roots and require one or two sum- 

 mers to become fully grown. 

 They pass the first winter as 

 grubs living deep down in the 

 ground and the second summer 

 are much larger and more 

 destructive than the first, so 

 that those fields left in sod one 

 year are likely to be badly in- 

 fested the next year. The 

 larva, ordinarily, pupates in 

 June or July of its second year 

 and after remaining a pupa for about three weeks, changes 

 into an adult beetle and remains in the ground until the 

 next spring. 



Control. — If the ground is badly infested with white 

 grubs or wire-worms, it should be given a thorough fall 

 plowing and either plowed again or thoroughly harrowed 

 in the spring. Land which has been in sod for many years 

 would ordinarily need this treatment. Potatoes should 

 not be planted immediately upon such ground, but it 

 should be planted for a year or two to such crops as buck- 

 wheat or some of the other small grains which are damaged 

 but little by white grubs or wire-worms. 



Fig. 12. White grub and 

 May-beetle. 



Wire-worms (several species) (Fig. 13) 



These insects do much damage to the roots of many crops, 

 including the potato. Like the white grubs, they normally 

 live in sod ground and feed on roots, and are not usually 



