REPORT OF COMMITTEE ON PUBLICATION 245 



no inclination to place her eggs, on or in close proximity to the base of the 

 cane, but scatters them about promiscuously over a space twenty feet or 

 more in diameter surrounding the vine. The eggs are very insecurely 

 attached and practically all of them fall to the ground before hatching. 



About 400 eggs are laid, on an average, by each female, and the eggs 

 require about three weeks in which to hatch. 



The Larva. 



The larva is a whitish grub with a brown head which attains, when full 

 grown, a length of about 1% inches. The body is rather slender, distinctly 

 segmented and has a sparse covering of short, s.tiff hairs. It is in the larval 

 stage alone that the insect is capable of injuring the vine. 



When the borers first appear from the egg they are only about 1/25 of 



an inch in length. The egg, as has been explained, is on the ground at the 

 time of hatching and when the borers issue from the eggs they burrow at 

 once into the soil. There they move about until chance leads them to a 

 grape root, which, when found, they attack at once. The little borers are 

 capable of living in the soil for several days without food, but it seems 

 probable that many of them die in a fruitless search for a suitable root from 

 which to obtain nourishment. In arriving at the root in this way, many of the 

 borers enter at a considerable distance from the vine and leave a section of 

 the main part of the root uninjured. The writer found one borer that had 

 evidently penetrated eleven inches of solid clay soil and had entered the 

 root at a point nine feet out from the vine. 



The young borer, after finding a suitable root, first eats a hole through 

 the bark and then excavates an irregular burrow, which, at first, is confined 

 to the softer portions of the bark. In the beginning the burrow may encircle 

 the root several times, but later, as the borer increases in size, it is made to 

 run with the grain of the wood and may extend either away from or toward 

 the base of the root. After the borers have been feeding several months 

 their burrows are so large that in roots half an inch or less in diameter all 

 the solid part of the root is converted into frass and only a thin membrane of 

 the outer bark remains intact. In larger roots the burrow will frequently 

 include all the wood on one side of the heart and is most likely to extend 

 along the under side of. the root. 



The habit of the borer of feeding so far out on the root makes the 

 practice of "worming" with a knife and wire impracticable. It has the 

 advantage, however, of often leaving a stub of sound root to help sustain 

 the vine. Often a root will be found completely severed by the borers and at 

 the wounded end of the remaining stub a vigorous growth of young roots 

 will be developing. Such severe root pruning lessens very greatly the feed- 

 ing area of the root system and reduces the vigor and productivity of the vine. 



The borer probably remains in the root for a period of twenty-one or 

 twenty-two months, the time including two winters. The first winter it evi- 

 dently feeds more or less during mild weather but remains inactive during 

 the second winter within a silk-lined hibernaculum located in the burrow. 



