Clover Insects 



685 



York State in tlie late seventies and first attracted attention by 

 its destructive work in Yates County in 1878. The introduction 

 of this pest has had an important effect on clover-growing in the 

 state because where the insect is present it has not been found 

 practicable to keep fields in clover longer 

 than the second summer after seeding. 



In addition to red clover, the clover 

 root-borer also attacks mammoth clover, 

 alsike, and to some extent alfalfa and peas. 



If one digs up a two-year-old clover 

 root in late fall or early spring it will be 

 found hollowed out by the longitudinal 

 burrows of a small brownish-black beetle 

 about one-tenth inch in length. (Figs. 

 658 and 65D.) The insect passes the 

 winter mostly in the beetle stage although 

 occasionally a fe-^ of the grubs are found. 

 In May or June the beetles leave the roots 

 and fly to other clover plants, preferably 

 those just beginning their second year of 

 growth. The beetles usually burrow 

 down through the crown, but they may 

 occasionally enter the root from the side. 

 The female deposits her minute, white, 

 elliptical eggs along the side of her bur- 

 row, covering them with bits of refuse. 

 The eggs hatch in a few days and the 

 young grubs burrow lengthwise through 

 the root, most of them becoming full 

 grown the last of July, although some do 

 not reach maturity until iSeptember. The 

 full-grown grub is about one-eighth inch 

 in length, white, with a yellowish head and brown jaws. It trans- 

 forms to a white pupa at the end of its burrow. Most of the 

 pupae change to beetles before the first of October. There is 

 only one generation annually. When the root is badly infested 

 the plant is severely injured, and if di-y weather ensues the top 



Fig. 658. Clover Root, 

 Showing Work of the 

 Borer. 



(Redrawn after Webster) 



