78 MASSACHUSETTS HORTICULTURAL SOCIETY 



year bees were provided in the orchard which had previously failed 

 to fruit, resulting in a crop on which the owner netted $3,000. 



Pears. The authority which is usually quoted for the pollina- 

 tion of pears is Norman B. Waite, in his publication of the United 

 States Department of Agriculture, entitled "The Pollination of 

 Pear Flowers." He says, "The common honey-bee is the most 

 regular important and abundant visitor and probably does more 

 good than any other species." According to Professor Waite, 

 moreover, "pears require cross pollination, being partially or 

 wholly incapable of setting fruit when limited to their own pollen. 

 Some varieties are capable of self-fertilization. Varieties that are 

 absolutely self-sterile may be perfectly cross-fertile." These are 

 but a few of the thirteen or more conclusions which are drawn 

 regarding the cross-pollination of pears. A thirteen per cent set 

 of pear bloom is considered an average fruit catch, while a five to 

 six per cent catch gives a heavy apple crop (ten to fifteen per cent 

 is rare). 



Plums and Prunes. A. H. Hendrickson ^ has been investigating 

 prune and plum pollination during the past several -.years. Obser- 

 vation in 1915 was made of 50,000 plum and prune blossoms, and 

 in 1916, 87,000. These observations have enabled him to draw the 

 conclusion "that all varieties of the Japanese group of plums 

 (Prunus triflora) are self-sterile with the possible exception of 

 Climax. Varieties of this group seem to cross-^Uinate readily. 

 Of the European varieties of plums (Prunus domestica) Tragedy 

 and Clyman show distinct evidence of self -sterility." 



Of the prune, the French and Sugar prunes seem to be self -sterile 

 to some extent. Robe de Sergeant and Imperial prunes are dis- 

 tinctly self-sterile. They, however, seem to cross-pollinate satis- 

 factorily. 



These observations were the result of a noticeable lack in the 

 setting of certain orchards. The normal set of French prunes was 

 about 4% as compared with 19% which was covered with a mos- 

 quito net tent under which bees were confined. Thus it has been 

 concluded that the " French prune at least may be aided in setting 

 a satisfactory crop by the presence of a large number of bees in the 



' University of California Bulletin, 274, "The Common Honey-bee as an Agent in Prune 

 Pollination." 



