94 FIELD CROP PRODUCTION 



which hatch from them require from three to five years to com- 

 plete their growth. The second year after grass land has been 

 planted in corn, the larvae feed upon the newly planted kernels 

 and upon the roots of the young plants. Serious damage some- 

 times results. Quite frequently it becomes necessary to replant 

 the field. The larvae become full grown in midsummer and after 

 pupation, which lasts three or four weeks, the adult beetles 

 appear. The adults fly to the grass lands and deposit eggs for 

 a new brood. No satisfactory method has been recommended 

 to prevent their ravages. They may be held in cheek quite 

 effectively by fall plowing, which kills many of the larvae, and 

 also many of the adults. The practice of a short rotation, 

 which allows the field to remain in grass but one year, will 

 largely prevent their increase to such numbers as would seriously 

 injure the corn crop. 



74. The grub-worm. — The large May beetles or June bugs 

 which are numerous during early summer are the parent form 

 of the white grub-worm. Like the click beetle, the June bug lays 

 its eggs in the meadow and pasture lands, usually in June or July. 

 The young grubs live upon the grass roots, and require about 

 two years to become full grown. When sod lands are plowed 

 and put into corn, the grubs, being deprived of the grass roots, 

 attack the roots of the corn. If the field has been in grass for 

 some time previous to plowing, the grubs may be numerous, and 

 since there are so few corn plants in oomparison to the grasses 

 per acre, many grubs may be found at work on the roots of one 

 corn plant. As many as 25 grubs have been found on one hill, 

 in fields that were badly infested with them. When the grubs 

 are numerous, they do serious damage, sometimes destroying the 

 entire crop. The most effective means of controlling them is, 

 as in the case of the wire-worm, the use of a short rotation and 

 practicing summer or fall plo\\dng. Sometimes if hogs are turned 

 into the field they will follow the plow and destroy many of the 

 grubs. 



75. The cut-worm. — The cut-worm is a common foe of 

 many farm and garden crops. It gets its name from its well- 

 known habit of eating only as much as is necessary to cut off the 

 plant, thus leaving a path of destruction as it proceeds from plant 

 to plant. The adult form is a moth, which laj^s its eggs princi- 

 pally in sod lands. The eggs are laid in midsummer and the 



