16 



Pollination. 

 The question of pollination is important where large quantities of Japanese 

 and Americana varieties are grown, but not so important where the domesticas are 

 in evidence. Most varieties of Japanese and Americana are self -sterile ; that is, 

 the varieties will not pollinate or fertilize themselves. Cross fertilization is much 

 stronger. Damson and Domestica varieties are not self-sterile, as far as the present 

 evidence will permit of a final judgment, but they are stronger and more likely to 

 produce abundantly when cross pollinated. Japanese varieties are readily pollinated 

 by Americana varieties that blossom at the same time. 



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Heine Claude in midsummer of the 

 third year. 



A large block of Burbank or a large block of Abundance will not pollinate 

 freely if isolated, but if the blocks are near each other or the -rows mixed through, 

 pollination will be almost certain. The same might be added with regard to Eed 

 June. The popular American varieties, De Soto and Hawkey e, are self -sterile, as 

 is also the popular Nigra variety Cheney, but they all cross pollinate readily. On 

 the other hand, a large block of domesticas, say Bradshaws, will produce well even 

 when isolated from other varieties. 



The question of the " June Drop " might be taken up here. By this I mean 

 the falling of a large number of fruits soon after the blossoms fall or even when the 

 fruits are the size of beans, and in a few cases very much larger. The fruit turns 

 yellow, shrivels up and falls off. 



There are two main causes of this drop — weak pollination and attacks of Plum 

 curculio. 



