76 INSECTS AFFECTING VEGETATION 



flight it so closely resembles some of the common wasps of the genus 

 Polistes that a close scrutiny is necessary in order to make sure that 

 the insect under observation is a moth and not a wasp. As a result 

 of these peculiarities the insect may be abundant in a locality and 

 yet remain unnoticed by grape growers. 



Vines when attacked by the borers do not often die as a direct 

 result of the injury sustained, but may become so enfeebled that the 

 annual growth of bearing wood is meager and the yield of fruit, 

 very small. 



It is in the Iarva3 stage alone that the insect is capable of doing 

 any injury. When first hatched the larvae are very small, being only 

 about one twenty-fifth of an inch in length. They are whitish in 

 color with brown heads, and are sparsely covered with stiff hairs. 

 When full grown some specimens attain a length of one and three- 

 fourths inches. As soon as the young borer is out of the egg, which, 

 as stated, is on the ground at the time of hatching, it begins to work 

 its way downward through the soil, evidently trusting good fortune 

 to guide it to a grape root. That the borers can survive at this early 

 age for several days with but little food was ^hown by placing half a 

 dozen in a small bottle, where they lived for three days and then 

 escaped by tunneling through the cork stopper. During the three 

 days' confinement they had no nourishment except what they might 

 have extracted from the dry cork, which was most likely very little. 



The borer, after finding the root, first eats its way through the 

 outer bark and then begins to excavate an irregular burrow, which 

 at first is confined to the softer portions of the bark. At the begin- 

 ning, this 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 be extended either toward or from the base of the root. 

 The diameter of the burrow is increased with the growth of the borer. 



The females, when they are engaged in egg-laying, can very 

 readily be approached and killed by striking them down with a 

 paddle-like instrument or board. If a watch is kept about infested 

 vines from the middle of July to the middle of August the females 

 may be seen and killed in this way. 



It is by the thorough cultivation of vineyards that the greatest 

 good is likely to be accomplished in the way of reducing the ravages 

 of this insect. Observation has shown that from the middle of June 

 to the last of July the insects are transforming from the borer stage 

 to the adult stage within cocoons which are located just beneath the 

 surface of the ground in near proximity to grapevines. If, during 

 this period the ground about the vines is thoroughly cultivated, most 

 of these cocoons will be either thrown to the surface where the pupae 

 within will perish, or be buried so deeply that the moths escaping 

 later will not be able to work their way out of the soil. The cocoons 

 are usually found a foot or more away from the vines, a fact that 

 enables the cultivator to reach most of them without the necessity 

 of working up entirely to the vine, which is a difficult thing to do 

 where some methods of pruning are practiced. As a matter of course, 

 tile cultivation will give the vines increased vigor, enabling them more 



