UNCLASSIFIED PESTS 347 



relished by white (i:rul)s and may be used as intermediate crops 

 between sod and vegetables. As previously stated, the grubs 

 do the greatest injury during the season following that in which 

 the eggs are laid. Observations in Illinois have shown that the 

 beetles prefer to lay their eggs in ground that is well covered 

 with vegetation. Pasture land, wheat, and oats are chosen 

 in the order named. Clover is a relatively immune crop, 

 very few eggs being laid in fields where there is a heavy stand. 

 These facts should be kept in mind when planning a rotation 

 of which vegetable crops are a part. 



In some parts of the country, white grubs appear in more or 

 less definite broods and are destructive in three-year cycles. 

 In localities where this tendency is well developed, this knowl- 

 edge may be utilized to avoid injury. 



WiREWORMS 



Several Species of Elateridoe 



Many vegetable crops are liable to attack by wireworms es- 

 pecially when planted on land previously in sod. Wireworms 

 (Fig. 217) are elongate, hard- 

 shelled, brownish larvse, the im- 

 mature stages of medium-sized, 

 dull-colored, snapping beetles or 

 click-beetles. Thev are under- ^ ,,_ . . 



^ Fig. 21/. — A wireworm, Mono- 



ground msects that eat olt the creindius ih-idus {x li). 



smaller roots, bore into tubers 



and fleshy roots and destroy germinating seed. The beetles 

 appear in May and June, and the females deposit their eggs 

 in the soil. The beetles are from i to |^ inch in length, dull 

 grayish brown in color, and have the peculiar habit of snap- 

 ping themselves into the air when laid on their backs. The 

 larvae feed on the grass roots for several seasons, the various 

 species differing in the length of their life cycle from three to 



