346 MANUAL OF VEGETABLE-GARDEN INSECTS 



transforms to a delicate whitish pupa. The insect remains in 

 this condition until the latter part of the summer and then 

 transforms into a beetle. It remains in the earthen cell until 

 the following spring, when it emerges from the ground. While 

 certain species emerge the second spring after the eggs are 

 laid, and a few do not emerge until the fourth spring, the 

 greater number of the injurious species do not emerge until 

 the third spring. For instance, in the last case the young 

 grubs that hatch from eggs laid in the spring of 1918 feed until 

 the fall of that year, hibernate during the winter of 1918-19, 

 feed again through the summer of 1919, hibernate again as 

 grubs during the winter of 1919-20, complete their growth, 

 pupate, and transform to beetles that season and hibernate 

 as beetles during the winter of 1920-21 ; the beetles emerge 

 in the spring of 1921. It will be seen from the foregoing ac- 

 count that the grubs are most destructive during the second 

 season, because it is then that they feed for the longest period 

 and make their greatest growth. The first year the grubs 

 feed only during the latter part of the season and are very small. 

 The third summer they feed only during the early part of the 

 season and only enough to prepare themselves for pupation. 



In case infested sod land is broken up and planted to vege- 

 table crops, the white grubs are forced to concentrate their 

 feeding on the latter. Corn, potato, beet and other root crops 

 are especially liable to attack ; in fact, there is scarcely a vege- 

 table crop that is not subject to injury when grown on infested 

 land. 



Crops liable to injury by white grubs should not be planted 

 on land known to be infested. Much trouble may be avoided 

 by adopting a short rotation of crops in which land will not be 

 left in sod for more than two or three years. White grubs are 

 likely to be abundant in old strawberry beds and when these 

 are plowed up they should be treated the same as sod land. 

 Buckwheat, alfalfa, clover and other leguminous crops are n(;t 



