ENTOMOLOGY 77 



readily to withstand and overcome the attacks of root-borers and other 

 insects. (W. Va. Bui. 110.) 



The California, Grape Root-Worm.* This is an insect that at- 

 tacks both the roots and the growing parts of the vine above ground. 

 It has been known to attack the leaves of the vine in this State for 

 a good many years^ but until a year or two ago it was unknown as 

 a root feeder. It is similar in its life history and mode of attack to 

 the well-known grape root-worm of the Eastern States, which is one 

 of the worst pests that the vineyardists there have to wage war 

 against. Our species has been doing considerable damage during the 

 past two or three years, and it promises to be an important enemy of 

 the vine in California. 



While the insect has occurred on vines in the State for the last 

 thirty years it seems not to have spread so rapidly as might have been 

 expected, judging from the experience with the same insect in 

 Europe and its related species in the Eastern States. It is difficult 

 to explain just what may account for this. 



Since the greater part of the insect's life is spent in the ground, 

 it is in this stage that conditions would be most likely to influence 

 its progress. Such conditions might be found in the kind of soil, the 

 cultivation of the soil, the variety of vines and the great depth of the 

 root systems in some of our drier sections. Again, the true importance 

 of the insect's work has never been appreciated in the State hitherto, 

 since it has been known as a leaf feeder entirely. Vines, therefore, 

 may have shown a general unthriftiness due to its attacks, but be- 

 cause the root infesting habits of the larvae were unknown the trouble 

 may have been assigned to other causes. 



The young larva upon hatching from the egg makes its way to 

 the ground almost immediately. It may crawl to the ground, as we 

 infer from finding them pretty well scattered down the trunk of the 

 vine, or they may possibly in many cases simply drop to the ground. 



As soon as the larvae reach the roots of the vine they begin feed- 

 ing, and it is generally the smaller rootlets that are first attacked, 

 although we have found young larvae around roots of considerable 

 size. These smaller roots may be eaten off entirely. The larger 

 roots are injured by the larvae gouging out long strips of the bark, 

 which sometimes take almost any direction, but on the roots of 

 medium size these strips are usually eaten out in a direction parallel 

 with the axis of the root, or in a spiral direction. The frass or eaten 

 bark is left in their paths and is characteristic of their injury. The 

 furrows made are from one-tenth to one-fifth of an inch wide, and in 

 cases of severe injury all the bark may be eaten away from the roots. 

 This feeding is continued from the time they hatch in the spring 

 until the vine becomes dormant in the fall. 



There are two forms of the adult beetle occurring in the State, 

 one being black in color and the other mostly brown. There is con- 

 siderable differences in the size of different specimens, and particu- 

 larly in the sexes the males being much smaller. On an average 

 they will measure about one-fifth of an inch in length. 



*See page 321, for illustration. 



