THE GEAPE ROOT-BORER. 23 



to the vine roots, no examination was made and positive evidence of 

 their presence is lacking. A number of old vines are known that 

 have been infested constantly for at least 10 years. In cases where 

 these vines have been pruned, cultivated, and fertilized a strong 

 annual growth of wood is still made and the crops of fruit are satis- 

 factory. Infested vines when neglected, however, in all cases ob- 

 served have practically ceased growing and died by degrees over a 

 period of several years. 



NATURE OF INJURY. 



Injury to grapevines by the root-borer is due exclusively to the 

 burrows made by the larvae in the roots (PI. Ill, A, B), and is usually 

 in the nature of severe root-pruning. The newly hatched larvae 

 enter the ground in the vicinity of grapevines and penetrate the soil 

 in search of roots, attacking them wherever found. Usually roots 

 smaller in diameter than an ordinary lead pencil are not made a 

 place of permanent attack. Those half an inch in thickness, and 

 often those that are larger, are girdled or eaten entirely off, only a 

 stump of live root being left to help sustain the vine. Frequently 

 all the main roots of a vine will be severed at varying distances from 

 the root center. In such cases the remaining root stumps hasten to 

 send out branch roots, the vigor and extent of growth of the branches 

 depending largely upon the cultural care the vine is receiving at the 

 time. 



DESCRIPTION. 



THE EGG. 



(PI. Ill, E.) 



The egg is 1.1 mm. long by 0.7 mm. wide, chocolate brown, oblong 

 ovate, and flattened; one end is slightly truncate, and a broad furrow 

 extends longitudinally on one side. The surface, except in the fur- 

 row, is finely and distinctly reticulate. 



Eggs hatch in from 18 to 23 days. 



THE LARVA. 



(PL III, A, B.) 



When first hatched the larva is dingy brown and about 2 mm. 

 in length. After the first or second molt the color changes to white. 

 The head is brown and the body is distinctly segmented and covered 

 sparsely with short, stiff hairs. Full-grown specimens are from 35 

 to 40 mm. in length. The larva stage covers a period of nearly two 

 years. 



