68 



Self -fertilized pears are deficient in seeds, while crosses are well supplied with 

 sound seeds. Even with those varieties that are self-fertile the pollen of another 

 variety is prepotent; the normal typical fruits are crosses. 



The Plum. Experiments showed that " out of 153 blossoms covered of the 

 Arkansas Lombard no fruit set; that out of 457 blossoms covered of the Wild 

 Goose (Prunus Americana) no fruit set; and that out of 90 blossoms covered of 

 the Japanese plum (Maru) no fruit set." 



Prof. Waugh (Rep. Vt. Agr. Exp. St. 1897-8, p. 237) found the following 

 insects pollinating the plum: honey bee, bumble bee, wasp, and some short-tongued 

 bees. 



In experiments carried out in 1907 at Denton, Md., Prof. Waugh secured the 

 following results : 



Of 490 blossoms that were covered belonging to Japanese varieties of plums 

 none set fruit; of several covered blossoms of the Wild Goose varieties none set 

 fruit; and of 449 covered blossoms of the Chicasaw group none set fruit. On the 

 other hand, unprotected blossoms of the same varieties had a moderate crop of 

 fruit, due to the very unfavorable weather conditions during the blooming time. 



With regard to the question, " Are the visits of insects really necessary to 

 poUination," Prof. Waugh continued his experiments at Denton, IMd., in 1908, 

 with the folloT\ing results: 



On 457 covered blossoms of chicasaw varieties no fruit set; on 216 covered 

 blossoms of Japanese varieties no fruit set; on 457 covered Wild Goose plums no 

 fruit set. On the other hand, the unprotected blossoms set a fair crop of fruit in 

 spite of unfavorable weather. 



Professor Waugh says, " These results indicate that insect visits are of prime 

 importance in the pollination of plums. Observation in the field shows that the 

 common honey bees are nearly always the most active workers, and the ones which 

 by the character of their operations in the flower, may be held chiefly responsible 

 for the proper distribution of pollen."— (Rep. Vt. Ag. Exp. St. 1897-8, pp. 246-247). 



Mr. C. H. Hooper (Jour. Roy. Hort. Soc, March 1912) found that when 

 insects were excluded from Gooseberries, Red and White Currants, practically 

 no fruit was formed; from Cherries not a single fruit set; from Plums a few set 

 fruit; from Apples, out of 63 varieties on which unopened blossoms were enclosed 

 and left untouched the only one on which fruit set and matured was Irish Peach; 

 and from Raspberries fruit set but the results were not so good as with flowers 

 exposed. 



