218 MANUAL OF AMERICAN GRAPE-GROWING 



covering of short, stiff hairs. These larvae burrow into the 

 grape-root, at first confining themselves to the softer portions 

 of the bark, often encircling the root several times, but later 

 bore with the grain of the wood and by the end of the season so 

 destroy the roots as to leave only the thin membrane of the 

 outer bark intact. This pest is difficult to deal with. The 

 borers cannot be removed by "worming" as in the peach, 

 and neither can the roots be protected by sprays or washes. 

 No one variety of the grape seems more immune than another. 

 Thorough cultivation in the months of June and July to destroy 

 the insects while in their cocoons at the surface of the ground 

 seems to be the only method of stopping their ravages, and this 

 is not always effective. 



FUNGOUS DISEASES OF THE GRAPE 



The grape is ravaged by four or five fungous diseases in 

 America, unless the utmost vigilance is exercised to keep the 

 parasites in check. Happily for commercial viticulture, there 

 are regions, as we have seen in the description of grape regions 

 in Chapter I, so fortunate in their freedom from fungous diseases 

 that there is little uncertainty in grape-growing and but small 

 expense in controlling diseases. Also modern science has 

 discovered the life history of all the important diseases and 

 devised fairly effective means of combating them. 



All of the fungous parasites of the grape in America are in- 

 digenous, having long subsisted on wild vines. They are, there- 

 fore, all widely distributed, and as cultivation has presented 

 to them great numbers of grape plants in continuous areas, 

 the diseases have increased rapidly in intensity, at times have 

 swept like wildfire through grape regions devastating and 

 utterly ruining great areas of vines. Means, however, are now 

 at hand in remedial and preventive treatment, which, while 

 because of cost may not permit the grapes to be grown profit- 



