• 9- 



Pistil. Green if uninjured, 

 Brown if injured by frost. 



Young 

 fruit 



Undeveloped seeds. White 

 if uninjured. Brown or 

 black if injured. 



APPLE BLOSSOM 



Frost Injury to F lowers or Young Fruits 



If a frost comes, every fruit grower will want to know hov/ much 

 damage has been done. Since time must elapse for injured tissues to wann 

 up and change their appearance, the full amount of the damage may not be 

 apparent until afternoon or even the follov;ing day, depending on the tem- 

 perature. 



During blossoraingj the pistil is the part most easily hurt. The 

 normal pistil is light clear greon in color. Injured pistils first look 

 waterSoaked, then discolorod and wilted, and finally turn brown, shrivel 

 and die. Since normal pistils, following fertilization of the ovary, turn 

 brown, shrivel and die, this normal condition should not be confused v;ith 

 frost injury. 



When the young fruits have formed, the seeds are usually the most 

 tender. Normal seeds turn brown or black. ViTith apples the tissue just out- 

 side tlie seed cavity is sometimes injured. Although apples v/ith injured 

 seeds sometimes set, such apples are small or misshapen at maturity. Those 

 injured outside the seed cavity seldom mature. Sometimes the injury takes 

 the form of a loosened layer of cells around the small undeveloped fruit and 

 upper part of the stem. With peaches, the veins around the seed are the most 

 sensitive, then the seed and finally the flesh. The skin of a young fruit 

 which is badly injured by frost, turns yellovf and the fruit drops in a few 

 days. If injured only to the extent of a slight slipping of the skin, the 

 fruit may mature although it will show russeting or frost cracks at harvest 

 time. 



