THE PEARS OF NEW YORK 87 



only of superior inherent hardiness but also of hardiness Drought about 

 by conditions which enable the trees to enter the winter with unimpaired 

 constitutions. 



The pear is seldom injured by heat in the summers of New York. 

 Occasionally fruit and foliage suffer from long-continued heat in the dry 

 weather of a hot summer. More often the trunks of pear-trees are injured 

 by a blazing sun in late winter or early spring, especially when the sun's 

 rays are reflected by ice or snow and strike the tree intensified. Indeed, 

 sunscald so produced is one of the common troubles of the pear in New 

 York. With the pear, as with all other fruits, there is a sum total of heat 

 units above a certain temperature, put by most experimenters at about 

 43° F., the awakening point of growth, necessary to carry the crop from 

 blossoms to proper maturity. Of the number of units necessary to mature 

 a crop little is known. Many varieties do not ripen in New York in a 

 cold season, but come to perfect maturity in warm seasons. A study of 

 phenology would throw much light on the failure of pears to ripen properly. 



The average date at which the last killing frost occurs in the spring 

 helps to determine the limits in latitude and altitude at which the pear can 

 be grown in New York. The pear blossoms early, and while both in bud 

 and blossom the reproductive organs seem able to stand more cold than 

 those of the peach and sweet cherry, yet even in the most favored regions 

 for growing this fruit in New York a crop is occasionally lost from killing 

 frosts, and there are few years in which frost does not take toll in some 

 part of the State. Damage from frost must be expected when the 

 commonly recognized precautions in selecting frost-resistant sites are not 

 recognized. Little or nothing can be done in New York to prevent injury 

 from frost once trees have been set. Windbreaks, whitewashing, smudging, 

 and orchard-heaters are all failures in frost -fighting in this State. 



The pear-grower should know how the blooming time of the varieties 

 of pears he plants agrees in time with spring frosts. To do this he must 

 have weather data and must know the approximate date of blooming of 

 varieties. He ought also to be able to synchronize three of these phases 

 of climate — spring frosts, fall frosts, and the length of the summer — 

 with the ripening dates of varieties. Data as to the average dates of 

 spring and fall frosts can be obtained from the nearest local weather bureau. 

 The accompanying table gives the blooming and ripening dates of pears 

 grown at the New York Agricultural Experiment Station. Blooming 

 and ripening dates vary in different parts of the State, and to make use 



