New York Agricultural Experiment Station. 405 



it came. There is a great difference in the quantity of pollen 

 produced by the varieties of the several fruits but it is doubtful 

 if insufficiency of pollen is a factor of much importance in the 

 failure of trees to set fruits. 



Varieties that do not set fruits often have abnormal or abortive 

 pistils or stamens. A high percentage of abnormal flowers nearly 

 always indicates a weakness in fruit setting. Another cause of the 

 failure to set fruits is the difference in time of maturity of 

 stamens and pistils. When these organs do not mature at nearly 

 the same time, fruits do not set unless pollen is supplied from 

 some other source. The female organs of fruits are receptive, 

 however, for several days and the pollen is not shed at once from 

 all anthers and is produced with such prodigality as in most cases 

 to insure the pollination of late-maturing stigmas. 



The solution of tho problem of self sterility in the main, then, 

 is to so plant that varieties will be cross fertilized. It is obvious, 

 if cross pollenization is to play an important part in fruit grow- 

 ing, in planting to secure it varieties must be chosen which come 

 into blossom at the same time as those that they are expected to 

 fertilize. 



There are several causes of dropping other than lack of fertili- 

 zation that need the attention of fruit growers. 



Weather conditions have much to do with the dropping of 

 fruit. Prolonged cold saps the vitality of young fruits and causes 

 many of the more tender ones to perish and let go their hold upon 

 the tree. Rain, whether a dashing shower or a prolonged drizzle 

 at. a low temperature, or even an extremely moist atmosphere 

 without a fall of rain, weakens the chances of full development of 

 fruits if such conditions prevail soon after fruit formation. Some- 

 times a lack of light causes fruit to drop, and thus we may ex- 

 plain the greater number of fruits at the tops of trees, on well 

 pruned trees, in open-centered trees and in orchards not thickly 

 planted. 



The " June drop," especially of the peach, may be explained 

 in part, as folloAvs : When fruits reach a certain size the food 

 stored in the tree the previous year is exhausted. ISTow if the 

 leaves of such trees are not fully expanded and if they are not 

 able to furnish a new supply of food, the young fruits often 

 drop. The June drop is especially liable to take place if there be 

 one or more of the unfavorable conditions mentioned in the previ- 

 ous paragraphs. With some fruits there is a tendency to drop 



30 



