The following paper was read by T. V. Munson : 



Resistance to Cold, Heat, Wet, Drought, Soils, 

 Insects, Fungi, in Grapes. 



BY T. V. MUNSON, Denison, Texas. 



As a general, if not a universal, law of adaptation of plants 

 to environment, we find that the natives in the environment are 

 better adapted than the exotics. 



The vine is no exception to this law. Let us test the asser- 

 tion by comparison. 



What species and varieties of grapes resist winter's cold 

 best? Certainly the vines, and vineyard varieties derived there- 

 from, native in cold regions, known as Vitis vulpina (riparia), 

 northern section of V. Idbrusca, V. cordifolia, northern section, 

 V. bicolor, V . tinerea, northern section, V . rubra. 



Of these, V. vulpina of Wisconsin, Minnesota and Dakota 

 readily endures without protection, 40 to 50 F. But vul- 

 pina of Virginia and northern Texas can endure only 15 

 to 20. The Labruscas of Massachusetts can withstand 20 

 to 25, while those of South Carolina perish in 10 to 15. 

 The cordifolia of central Illinois and Ohio (about the north- 

 ern limit of this species) endures 15 to 25, while the 

 Florida cordifolia is sometimes killed to the ground in northern 

 Texas with zero or a few degrees colder. V. bicolor of south- 

 ern Wisconsin endures 30 readily, while Norton Virginia, of 

 the nearly allied species of aestivalis, finds its northern limits 

 about Louisville and Cincinnati. So we might continue with all 

 the species and their varieties. 



The limiting lines of hardiness to withstand cold do not 

 follow the parallels of latitude, but the isothermal lines. Hence 

 we have wild grapes in northwest Texas that readily endure the 

 winters of Massachusetts, and the Vitis California, found along 

 Rogue River in southern Oregon, its extreme northern range 

 winter-kills to the ground, when grown at Denison, Texas. 



