244 INTERNATIONAL CONGRESS OF VITICULTURE 



The injury to the vine is done by the larva, or borer, burrowing through 

 the roots, the attack usually being made a foot or more out from the center 

 of the root system. Badly infested vines will have all or most of the main 

 roots killed except stubs at the base a foot or so in length. These root-stubs 

 will afford the vine a sufficient hold in the soil to retain life but will not 

 permit it to make a satisfactory growth or produce a normal crop of fruit. 

 Vines may thus become stunted and unprofitable without presenting any 

 external symptoms whereby the vineyardist can determine the cause of the 

 trouble. 



Distribution. 



The grapevine root-borer is native to North America and is especially 

 destructive in certain localities of the Appalachian region of the United 

 States. The species is known to occur as far west as Missouri, but the most 

 severe injury to grape vines has been reported from West Virginia and 

 Kentucky. It is probable that this borer attacks all varieties and species of 

 cultivated and wild grapes that grow within its range. In the vineyard the 

 insect shows no preference for particular varieties. 



LIFE HISTORY. 

 The Egg and Oviposition. 



In the latitude of West Virginia the adult moths appear during the latter 

 part of July and remain on the wing for two or three weeks. Observations 

 made by the writer show that the females issue from the cocoon early in 

 the day, fertilization, as a rule, takes place in the afternoon of the same day 

 and egg-laying begins on the following day. 



The egg is oval in outline, slightly flattened, with one face evenly convex 

 and the other marked through the center with a deep longitudinal furrow or 

 groove, the shape of the egg being not unlike that of a grain of coffee. The 

 length is slightly less than .04 inch and the width about .025 inch. The color 

 is chocolate brown, the surface being finely and densely punctured and 



Fig. 9. Larvae of the grapevine root-borer attacking a root. 



marked with a network of delicate lines. Eggs are deposited singly, or 

 rarely in pairs, upon the leaves or stems of weeds, blades of grass, straw or 

 any plants that may be growing or lying beneath the vines. Occasionally 

 they are placed upon the leaves or canes of the grape vines. The mo to. 



