As to soil, the law holds good so far as resisting an excessive, or injurious chemical element. 

 For example, some varieties of grapes, the Labrusca, Lincecumii and Rotundifolia varieties 

 especially, chlorose very badly (turn a pale sickly yellow in foliage) , if set in soils having above 

 forty per cent of carbonate of lime, while the Vinifera, Cordifolia, Cinerea, Berlandieri, Champini, 

 Candicans, Rupestris and Monticola thrive in such soils. We find those that chlorose badly are 

 natives of very sandy soils, along the banks of streams and lakes, or on sand hills, as is the Post- 

 Oak grape of Texas, while those that grow best in very limy soils, belong to species native in 

 such soils. 



We find, however, that in some cases varieties of species, native in very sterile soils, take on 

 far more vigorous growth when put into soils richer in humus and the chief elements of plant- 

 food; and this causes excess of wood and leaf-growth, to the detriment of fruit bearing, when 

 carried to the extreme. 



Nearly all species of grapes are native in warm, loamy, well drained soils, and such cannot 

 long endure with roots in permanent water or in cold, livery, compact clays, but a few species 

 are known, that cannot long survive in soils not sub-irrigated. Such are Vulpina, Rupestris, 

 Cordifolia, Cinerea, Rotundifolia and Simpsoni. The last named is often found with the roots 

 perpetually submerged in the borders of swamps and making immense growth. In such situa- 

 tions, the Vinifera, native on the limy hills of Southwest Asia, and Pc a *-Oak grapes Oi the Texa* 

 sand hills, would survive only a short time. 



In land that is seepy during rainy weather and some time after, but in. the dry, hoi gummers l 

 dries out and becomes hard, no grape thrives. Cordifolia, above all other species, perhaps, can 

 endure such situations longest. 



Concerning resistance to mildews, rots, etc., it is true that all species native in high arid 

 regions, are very quickly and destructively attacked by the cryptogamic parasites, when moved 

 into humid situations where such organisms exist. For resistance to these parasites, natives of 

 the parasitic regions must be sought. Perfectly resisting varieties in such regions, when hybrid- 

 ized with non-resisting varieties, produce only partially, or weakly resisting varieties. 



Take a vine from a parasitic region, loaded with the parasites of mildew and rot, and plant 

 it in an arid region, and it becomes free of these fungi, simply because the parasites must have 

 much moisture in the air to propagate. 



This law does not hold good as to root parasites, or bacterial blights that live within the 

 cells. For example, the Anaheim grape disease, of California, thrives in the moist regions of 

 Northern California as well as in the dry region of Southern California, where it originated, 

 just as pear-blight when once introduced into California and Colorado, is as contagious and 

 destructive as in Georgia or Texas. 



The insects that infest grapes know no specific bounds. The Rose Chafer, the Fidia, the 

 Leaf-Folder, the Leaf-Hopper, are just as bad in one region as another in which they can endure 

 the winters, and on one species as another with few exceptions. Certain varieties resist, or are 

 distasteful to these insects, and thereby escape, while others are greatly liked and damaged by 

 them. (See pages 230 to 235 for descriptions of insects.) 



The Leaf-Folder never hurts a vine that has leaves that are glabrous, that is entirely without 

 pubescence, or down of any kind on the upper side of the leaves. The egg is laid on upper side 

 and the larva, finding no pubescence to tie its webs to, and thus unable to draw the leaf together 

 over it, soon perishes in the sun, or is eaten by birds; hence only grapes with leaves more or less 

 downy on upper side of the leaves are damaged by the Leaf-Folder. 



There are some varieties of grapes much less bothered by the Leaf-Hopper, than others. 

 These generally are the varieties with very firm, dense tissue, such as the Post-Oak grapes of 

 Texas. The Fidia and Rose Chafers make little choice of kinds, and are voracious feeders on 

 the foliage. 



The Phylloxera comes well under the general rule. It can do little damage to those species 

 of grapes native in the same regions where the Phylloxera is native, yet there is much difference 



216 



