Frost Injuries and Protection, Secondary Bloom 325 



the assembled information leads to no conclusions. Few 

 fruit-growers have standard thermometers, and reports 

 can hardly be comparable; the temperature varies in 

 surprisingly small areas and fluctuates rapidly, and 

 minimum readings often mean little so far as portraying 

 true conditions is concerned. 



In a general way, it may be said that little injury to 

 fruit or blossoms occurs before the temperature falls 

 below 28 and remains there for some length of time. 

 Peach buds far enough advanced to show the pink in 

 the tips have safely passed through nights when the 

 mercury fell to 21, and in other cases a higher tempera- 

 ture has injured apples in the same stage. It is probable 

 that in the latter case the freeze was of longer duration. 

 Peaches fertilized and large enough to fill the "husk," 

 which surrounds them while young, have escaped unin- 

 jured, while the open bloom on apple trees not ten feet 

 away was killed outright. One cannot read the ther- 

 mometer and tell with assurance whether the crop is lost or 

 not, but within twenty-four hours after the freeze one 

 who knows how may easily estimate the extent of the 



injury. 



The Kinds of Frost Injuries 



Frost Russet. The light frost often leaves marks that 

 the fruit carries to maturity, an injury spoken of as " i 

 russet." On the mature fruit these marks of early injury 

 take various fantastic forms. Often it appears as a band 

 about the center of the fruit, as shown in Figure 87, 01 it 

 may appear as a russet area at either the calyx or stem end. 

 The position seems to differ with varieties. That shown 

 in the .figure is Chenango (Strawberry) apple. Unless 



