CHAPTER XXXIII 



POLLINATION 



Undoubtedly orchardists have observed apple trees which blos- 

 somed well but did not set a fair amount of fruit. Such a failure 

 may be due to a number of causes : 



1 . Poorly nourished fruit buds. 



2. Injury to the pistil during winter (not easily observed with 

 the eye alone). 



3. Injury to the blossoms by fungi. 



4. Injury to the blossoms by rain. 



5. Injury to the blossoms by strong or drying winds. 



6. Injury by insects. 



7. Lack of proper pollination (self-sterile and self- fertile trees). 

 Probably the most important factor is the last. Many times total 



failure in the setting of fruit is due to self-sterility. Properly speak- 

 ing, a self-sterile tree is one which, to bear well, must have other varie- 

 ties near it. But a tree is not self-sterile when it does not blossom. 



Self-sterile trees. The following varieties are more or less 

 self-sterile in New York State : Baldwin, Ben Davis, Fallawater, 

 Oldenburg, Rhode Island Greening, Red Astrachan, Smith Cider. 



A list from the West showing both self-sterile and self-fertile 

 varieties is interesting : 



Variety Pollen Bearers 



Arkansas Abundant 



Arkansas Black Medium 



Autumn Bough Medium 



Bailey Sweet Medium 



Baldwin Medium 



Ben Davis Medium 



Bietigheimer Shy 



Bough Abundant 



Canada Keinette Abundant 



Domine Medium 



Early Strawberry Abundant 



414 



