322 FUNDAMENTALS OF FRUIT PRODUCTION 



or lack of constitutional hardiness, there is a northern limit to the culture 

 of every variety and that limit is reached more quickly for some varieties 

 than for others. 



Varietal Differences. — Out of the vast and costly experiments in hardi- 

 ness carried on by planting and replanting, the sieve of selection has shown 

 certain varieties to withstand winter cold in average conditions better than 

 others. Since Baldwin is perhaps the best known single variety in most 

 sections where apple hardiness is important it is used as a standard of 

 reference. Hardier than Baldwin is a quaUty possessed by but few varie- 

 ties of extensive commercial possibilities though this statement does not 

 mean that Baldwin is particularly hardy. In the list of varieties recom- 

 mended by Hedrick, Booth and Taylor^* for the St. Lawrence and 

 Champlain Valleys, where Baldwin does not succeed, are Fameuse, 

 Mcintosh, Oldenburg, Wealthy, Blue Pearmain, Jewett Red, St. Lawrence, 

 Gravenstein, Red Astrachan, Yellow Transparent, Canada Baldwin, 

 Longfield and numerous crab apples. 



For ''the most northerly district" of Quebec, Macoun^^^ recommends 

 Tetofski, Blushed Calville, Lowland Raspberry, Duchess, Charlamoff, 

 Antonovka, Wealthy, Hibernal, McMahon, Longfield, Patten Greening, 

 Mcintosh, Milwaukee, Winter Rose, Stone, Scott Winter and Malinda. 

 It is stated that the summer and autumn varieties are the hardiest. 



At the Northwest Experiment Farm, in Minnesota, where winter con- 

 ditions are probably as severe as at any point where apples can be 

 expected to grow% the list of approved varieties is limited, aside from 

 certain crab apples, to four: Hibernal, Oldenburg, Okabena and Patten 

 Greening. ^^^ 



If one variety were to be picked as the hardiest of all cultivated 

 varieties of the apple grown in America it would probably be Hibernal. 



The Pear. — The pear is like the apple in its reactions to winter con- 

 ditions. It is somewhat less hardy than the apple. Though apples are 

 grown at points where the mean temperature of December, January and 

 February is 13°F., the northern limit of the pear follows in general the 

 mean temperature line of 20°F.'^^ Nevertheless certain varieties possess 

 considerable hardiness. Though evidence as to actual hardiness in the 

 northern Mississippi valley is not available because of the complications 

 introduced by fire blight prevalence, some information may be secured 

 from experience in certain eastern states where blight is not so serious. 



Pears suffered extensive injuries in New York during the extremely 

 severe winter of 1903-1904.^^ Young trees, though the bark and wood 

 were discolored, made good recovery, in one case forming a layer of 5 

 millimeters over the old sap wood in the first summer. Trees that had 

 been injured by psylla were killed outright in many cases. Dehorning 

 old trees that were injured aggravated their poor condition. 



Waite'^^ reports extensive damage to pears in the Hudson River 



