116 



PESTS OF GARDEN AND FIELD CROPS 



with washing the seed cane with whale-oil soap. Remnants of cane in 

 the fields, and Johnson grass in or near by, should be burned. 



The Clover Root-borer {Hylastinus obscurus Marsh.) 

 In the Central states clover is subject to considerable injury by this 

 insect, the presence of which is seldom recognized. The adult beetle 



is small, dark, and cylindrical. 

 Coming out in the spring from 

 clover roots, in which it has 

 passed the winter, it lays eggs 

 in shallow cavities which it ex- 

 cavates in the sides of the larger 

 roots of clover plants in the 

 same or adjoining fields. The 

 grubs that hatch from these eggs 

 burrow in and through the roots, 



Fig. 81.— Work of the Clover Root- 

 borer. Original. 



Fig. 82. — Adult of the 

 Clover Root-borer. En- 

 larged and natural size. 

 Original. 



sometimes completely destroying their central parts and killing 

 the plant. 



In the latter part of summer the grub changes to a pupa, from which a 

 beetle emerges in fall, but remains in the root until the following spring. 



Only two-year-old plants are likely to be attacked. Plowing a badly 

 infested field at once after haying will kill many of the grubs, because 

 the roots will be turned up and dried out. Pasturing a field serves to 



