•■.'J-EATHER FACTORS AFFECTING FRUIT PLAMTS IN 1 lASSACHUSETTS 



The temperatures that fruit buds and small developing fruits v/ill endure 

 are dependent upon many variable factors, such as the kind and variety of fruit, 

 the type of weather preceding a frost or cold spell, the vigor and nutrition of 

 the plant. 'Ihe following table is a guide for temperatures Tirhich approach the 

 critical level. Temperatures below these levels will generally cause severe 

 injury, although under certain conditions temperatures below these indicated may 

 not cause complete killing of blossoms and young fruits. 



Critical Temperatures for Flower Buds and Young Fruits 



Stage of Development 

 Fruit Delayed Dormant Pink Blossom Calyx to 1st Cover 



°F. 



29 

 28 

 30 

 30 

 28 

 30 



Peach buds are frequently killed by vdnter temperatures of -15°F. and under 

 some conditions -10°F, will kill dormant peach buds. Periods of mild weather 

 followed by a sudden drop to subzero temperatures will cause more killing than a 

 gradual decrease to subzero temperatures. 



Blueberries will stand slightly lower winter temperatures than peaches. 



Apples, pears, plums, and sour cherries are seldom injured by subzero ivinter 

 temperatures experienced in I'lassachusetts, although temperatures of -20°F, or 

 lower may cause injury in some seasons. Unseasonably low temperatures early in the 

 fall cause more injury than the same temperatures in the winter. 



Strawberries will, be injured by temperatures of 15°F, in the fall unless they 

 are protected by a winter mulch of straw or hay. 



During the months of September and October when the bulk of the apples are 

 harvested, high winds can cause considerable loss to the fruit grower by causing 

 the apples to drop to the ground as windfalls. Excessively high temperatures 

 (70°F, or higher) during this period will also cause an increase in the dropping 

 of apples, 



— W. D, V^feeks 



